Forestry and Forest Melioration

Growth of forest plantations of the Scots pine and English oak established by different types of planting material in the Right-Bank Forest-Steppe in Ukraine

O. H. Vasylevskyi — 2024-06-27

Introduction

Specifying the method for establishing forest plantations (for example, planting seedlings, saplings, cuttings, or sowing seeds) and the planting material type (containerized or bare-root seedlings) that would be optimal for the certain site conditions, largely determines the success of man-made forest regeneration.

The planted stands in the study region (Vinnytsia and Khmelnytskyi administrative regions in Ukraine) differ in establishment and cultivation technologies. It was found that growth features of forest plantations of the main forest-forming species, established with containerized and bare-root seedlings, were not investigated in the region, which makes the presented study relevant.

The study aimed to compare the growth characteristics and survivability of one- and four-year-old English oak and Scots pine forest plantations established by planting one-year-old containerized and bare-root seedlings in the Right-Bank Forest-Steppe in Ukraine.

Materials and Methods

Growth characteristics such as height, height increment, and root collar diameter of Scots pine and English oak seedlings in one- and four-year-old forest plantations established with different types of planting material as well as their survival rate were determined in September 2023. The study plots are situated in the branches Vinnytsia Forestry (Vinnytsia Region) and Slavutske Forestry (Khmelnytskyi Region) of the State Specialized Forest Enterprise “Forests of Ukraine” (Podilskyi Forestry Office). Forest plantations of English oak were established by planting one-year-old containerized seedlings grown in polystyrene cassette containers with a cell volume of 530 cm³ (Containerized oak treatment 1) and in plastic cassette containers with a cell volume of 265 cm³ (Containerized oak treatment 2) and by planting one-year-old bare-root seedlings grown in a greenhouse with irrigation (Bare-root oak treatment). Scots pine forest plantations were established by planting one-year-old containerized seedlings grown in plastic cassette containers with a cell volume of 120 cm³ (Containerized pine treatment) and by planting bare-root seedlings grown in a greenhouse with irrigation (Bare-root pine treatment).

The seedling survival rate in the first year of growth was evaluated as a ratio of viable plants at their registration to the initial number of planted seedlings, expressed as a percentage. The obtained data were processed by mathematical statistics using the MS Excel program package. The variability levels were assessed according to the scale of S. O. Mamaev.

Results

One-year-old English oak forest plantations established with containerized and bare-root seedlings (fresh relatively fertile forest site type). The height, height increment, and diameter of the oaks were the largest in the Containerized oak treatment 1 and were 34.4 ± 1.55 cm, 16.3 ± 1.04 cm and 5.4 ± 0.24 mm, respectively. The values in the Containerized oak treatment 2 were lower by 1%, 18% and 2%, respectively, and in the Bare-root oak treatment by 13%, 34% and 39%.

The survival rate for oaks in one-year-old forest plantations established with containerized seedlings was higher (85% and 93%) than in plantations established with bare-root seedlings (71%).

One-year-old Scots pine forest plantations established with containerized and bare-root seedlings (fresh relatively fertile forest forest site type). Height, height increment, and diameter of pines were greater in the Containerized pine treatment and were 22.1 ± 0.51 cm, 9.2 ± 0.39 cm, and 5.3 ± 0.19 mm, respectively. In the Bare-root pine treatment, the variables were lower by 18%, 17%, and 26%, respectively.

The survival rate of pine plants in one-year-old plantations established with containerized seedlings was also higher (93%) than in plantations created with bare-root seedlings (86%).

Four-year-old Scots pine forest plantations established with containerized and bare-root seedlings (moist relatively infertile forest site type). The height and height increment of the pines were greater in the Containerized pine treatment and were 122.3 ± 4.17 cm and 34.8 ± 1.63 cm, respectively. In the Bare-root pine treatment, the variables were lower by 6% and 7%, respectively. On the contrary, the root collar diameter was 7% greater in the Bare-root pine treatment than in the Containerized pine treatment.

Significant differences were absent between average height, height increment, and root collar diameter in the Containerized pine and Bare-root pine treatments.

Four-year-old Scots pine forest plantations established with containerized and bare-root seedlings (fresh relatively fertile forest site type). Height, height increment, and root collar diameter of Scots pines were greater in the plantations established with containerized seedlings and were 128.5 ± 5.52 cm, 40.5 ± 1.45 cm, and 32.2 ± 1.62 mm, respectively. In the plantations created by bare-root seedlings, the values were lower by 11%, 21%, and 21%, respectively.

A statistically significant difference in height, height increment, and root collar diameter was found between Containerized pine and Bare-root pine treatments.

Conclusions. The use of containerized seedlings is quite effective from a silvicultural point of view. For example, the better growth intensity of containerized seedlings and the high survival rate of plants in the forest area allow for a decrease in the initial density of the plantations by 12–30%.

The results obtained in the study should be used when developing guidelines for creating forest plantations in the conditions of the Right-Bank Forest-Steppe in Ukraine.

1 Fig., 4 Tables, 20 Refs.

Effectiveness of the use of plant growth stimulants when creating Scots pine forest plantations in Kharkiv Forest Research Station

O. M. Danylenko — 2024-06-27

Introduction

In recent years, there has been a tendency to increase the cultivation of the containerized planting material of the main forest-forming species. Plant growth stimulants are used in many countries to intensify the growth of planting material for many tree and shrub species. However, the use of plant growth stimulants in forestry is fragmentary.

This study aimed to assess the effect of plant growth stimulants on biometric characteristics, mass, and yield of standard containerized Scots pine planting material, as well as on mensuration indicators and viability of forest plantations established with such planting material in Kharkiv Forest Research Station.

Materials and Methods

Scots pine seedlings were grown in nursery conditions in agrotextile containers. During the growing season, two root or foliar feedings of seedlings were carried out with tested growth stimulants Tsyrkon, Hreynaktyv-S, Kornevin, Radifarm Plus, Aminostym, and Megafol in the norms recommended by the manufacturer.

The effectiveness of the tested plant growth stimulants during the cultivation of one-year-old Scots pine seedlings was evaluated by biometric characteristics and the mass of the above-ground (trunks plus needles) and root (roots) parts in an air-dry state.

Survivability in the first year of growth of forest plantations was determined as the ratio of the number of viable seedlings at the time of their accounting and those planted during the establishment of experimental plantations, expressed as a percentage. All preserved pine seedlings were measured according to treatments.

Results

The average height and the average diameter of one-year-old containerized pine seedlings were significantly greater in the treatments where root and foliar fertilizations with tested plant growth stimulants were applied. For example, the difference between the experimental treatments and the control was 21–52%, or 2.9–7.4 cm for the height and 7–20%, or 0.1–0.3 mm, for the root collar diameter.

The largest mass of the above-ground part of an average Scots pine seedling in the air-dry state was determined in the Megafol treatment; it was 1.24 g and exceeded the control value by 46%. |The smallest mass of 0.99 g was detected in the Radifarm Plus treatment; the excess over the control was 16%.

The largest mass of the root part of an average pine seedling was found in the Aminostym treatment; it was 0.62 g and exceeded the control by 59%. The smallest root mass of 0.49 g was recorded for the Radifarm Plus treatment with 26% excess over the control. The total weight of seedlings was 1.24–1.82 g.

The proportion of standard seedlings in the control was 76%, while in the experimental treatments, it was 86–98%.

Experimental one-year-old forest plantations were superior to the control by 4–30% in height, 1–18% in height increment, and 6–14% in root collar diameter.

Conclusions

Root and foliar treatment of seedlings with solutions of the tested growth stimulants Tsyrkon, Hreynaktyv-S, Kornevin, Radifarm Plus, Aminostym and Megafol in the conditions of the south-eastern part of the Left-Bank Forest-Steppe at the rates recommended by the manufacturer contributed to an increase in their biometric parameters and the mass of root and aboveground parts. The results showed both the higher mensuration parameters and survivability of one-year-old Scots pine forest plantations established using containerized planting material grown with the use of growth stimulants, as compared to the plantations established using both containerized planting material grown without growth stimulants and bare-root planting material.

4 Figs., 4 Tables, 25 Refs.

Forestry assessment of sod-podzol soils’ properties in the northern part of Zhytomyr Polissya

S. P. Raspopina — 2024-06-27

Introduction

Forest productivity depends on a complex of abiotic and biotic factors, among which soil properties are the most important. The search for relationships between forest productivity and soil properties has always been a relevant subject of scientific knowledge. The study aimed to assess the forest growth capacity of the soils in the northern part of Zhytomyr Polissia based on a comprehensive (field and analytical) investigation of the soil cover in the Olevske Forestry branch of the State Specialized Forestry Enterprise (SE) ‘Forests of Ukraine’.

Materials and Methods.

The forest growth capacity of the soils was assessed based on their forest growth effect, which was determined by the site class of forest stands using a set of basic soil indicators such as acidity, particle size distribution, humus content, and mobile forms of N, P, K.

Results

The soil cover is a variety of sod-podzolic soils of automorphic, semi-hydromorphic and soil-hydromorphic types, on which mixed (pine-birch) forests grow. In most cases, soils were formed on fluvioglacial sediments.

The studied soils have a sandy composition. The content of clay particles ranges from 2.62 to 25.12% and averages 8.16±1.80%. At the same time, sandy soils predominate (94%); light loamy soils make up only 4%. A light loamy composition was identified in one plot, where sod-podzolic soils were formed on the eluvium of chalk marls. Soils are characterized by a very acidic environment and low humus and nutrients (NPK) content. The studied soils had the following average indicators: рН_Н2О 4.6 ± 0.36, humus content – 1.54 ± 0.48%, Nitrogen – 2.64 ± 0.59 mg per100 g of soil, Phosphorus – 2.27 ± 0.58 mg per100 g soil, Potassium – 2.73 ± 0.77 mg per 100 g soil. The exceptions are soils formed on the eluvium of chalk marls. In these soils, acidity becomes neutral (pH = 7.7), the content of mobile compounds of N and P reaches an average level (N – 4.69 mg per 100 g of soil, P₂O₅ – 11.6 mg per 100 g of soil), and humus and K had a very high level (humus – 2.89%, K₂O 41.63 mg per 100 g of soil). Such changes in the chemical composition lead to an increase in the forest growth capacity of the sod-podzolic soil. The content of clay particles affects several properties of sod-podzolic soil, which, in turn, determine its forest potential. The content of clay particles has a linear, mathematically proven strong, and very high correlation with the content of humus and mobile compounds of K and N in the upper humus layer. For example, the correlation coefficient between the content of clay particles and the content of Nitrogen is 0.72, Potassium 0.83, and humus 0.91. The productivity of pine stands is also affected by the thickness of forest litter. Slowing down its mineralization in excessively moist habitats leads to an increase in the thickness of the litter, inhibits the biological cycle of substances, and negatively affects the tree stand nutrition which decreases forest productivity.

Conclusions

The stands of Pinus sylvestris have adapted to an acidic environment and low supply of soil with humus and nutrients and mainly grow according to site class I (II). Improving soil conditions leads to an increase in site class to Ia. A decrease in site class to III is explained by excessive soil moisture.

Among the studied soil indicators, the contents of clay particles, humus, and mobile N and K compounds have the greatest influence on the productivity of forest stands. It was determined and mathematically substantiated that a quantitative decrease in the average values of these soil indicators leads to qualitative changes in the forest stand, in particular, to decrease its productivity from site classes I to III.

3 Figs., 2 Tables, 19 Refs.

Features of the application of uniform shelterwood felling in pine stands in Polissia, Ukraine

V. P. Tkach — 2024-06-27

Introduction

The uniform shelterwood felling is an important silvicultural measure of close-to-nature forestry. Such felling type was applied in the pine stands in Polissia (forest zone of Ukraine) in small volumes in the past years. In many plots, the felling was not completed, and the cut areas were not sufficiently regenerated with pine and other valuable species. Often felling was carried out in years with poor pine seed production, and measures aimed to promote natural regeneration were not carried out. Therefore, different authors have obtained contradictory data on the success of natural pine regeneration after uniform shelterwood felling, as well as the feasibility of such type of felling. The aim of the study was to determine the specificities of uniform shelterwood felling in pine stands in Polissya zone and to assess the feasibility of their application in the context of close-to-nature forestry.

Materials and Methods

Active experiments were established in the mature pine stands in Eastern Polissia in Ukraine. The experiments involved different intensities of the first stage of uniform shelterwood felling (10–50%) with a decrease in relative density of stocking to 0.3–0.7 and measures to promote natural forest regeneration. In pine stands on permanent sample plots, trees were divided according to categories of health condition, Kraft classes, and classes of crown length along the trunk. The pine seeds were counted. Accounting for advance growth, self-sowing of tree species, and regeneration success evaluation were carried out on more than 100 plots in pine stands.

Results

In pine forests of fresh pine forest type with a decrease in relative density of stocking to 0.5–0.6 and natural regeneration assistance for 3–4 years, the pine regeneration was poor or insufficient. In pine stands in fresh oak-pine the relatively poor forest type with medium seed production after the first stage of felling with a decrease in relative density of stocking to 0.4, the pine regeneration was satisfactory. In the pine stands in wet oak-pine forest type with decrease of relative density of stocking to 0.4, the density of 3–4-year-old pine advance growth was 8.8–34.7 thousand stems?ha^-1, and in the plots with relative density of stocking of 0.3 it was somewhat smaller (9.1–11.3 thousand stems?ha^-1). Natural regeneration there was good and satisfactory. In the plots without assistance in regeneration, the number of pine advance growth was 1.8–4.0 times less and did not reach the standard indicators. In pine stands in fresh hornbeam-oak-pine relatively rich forest type after the first stage of felling, the regeneration was poor or insufficient. In pine stands at wet oak-pine relatively rich forest type, with a reduction of relative density of stocking to 0.5 and the laying of furrows, natural regeneration was satisfactory. After the second (final) stage of uniform shelterwood felling more than 79% of the pine advance growth survived, of which 58% were undamaged.

Conclusions

The natural regeneration after uniform shelterwood felling was the most successful in fresh and wet oak-pine relatively poor forest types. Felling should be carried out in years of good pine seed production, in stands with well-developed crowns, the length of which is at least one third of the height of the trunk, and poor cereal vegetation in the above-ground cover as well as undergrowth. It is advisable to reduce the relative density of stocking to 0.4 during the first stage of felling. A mandatory precondition for felling is early implementation of measures promoting natural regeneration by means of soil mineralization and preliminary removal of undergrowth. To ensure natural seeding of plots (if necessary) pine seeds should be undersowed. During the felling stages, the damage to the advanced growth of pine and other valuable species should be minimized.

1 Fig., 4 Tables, 23 Refs.

Elms (Ulmus L.) in the Branch “Myrhorod Forestry” of the State Specialized Forest Enterprise “Forests of Ukraine”

V. L. Meshkova — 2024-06-27

Introduction

Elms are spread in forests, landscaping settlements, and protective forest belts. After several waves of elm mortality from Dutch elm disease (DED) in the 20^th century, individual populations recovered or formed resistant hybrids. However, epiphytoties of bacterial and fungal diseases sometimes develop, particularly due to pathogen vectoring by bark beetles. In Ukraine, the spread of elms and their damage by different causes are relatively poorly investigated.

This research aimed to discover the features of Ulmus sp. distribution by stand origin, age, and forest site condition in the forest fund of the Branch “Myrhorod Forestry”.

Materials and Methods

The data as of 2010 and 2017 on the forest fund of enterprises belonging to the Branch “Myrhorod Forestry” of the State Specialized Forest Enterprise “Forests of Ukraine” were selected from the database of Ukrainian State Forest Management Planning Association “Ukrderzhlisproekt” using SQL-query and converted to the *.xls files.

Area distribution by types of forest site conditions was assessed following the Ukrainian school of forest typology. Such distributions for the entire area covered with forest vegetation, for subcompartments with elms in the stand composition, and with elms as the dominant species were compared for various elm species and stand origins, using c²-test. The percentages of stand areas of different origins and elm species in 2010 and 2017 were compared using z-test in the two proportions comparisons.

The data for subcompartments with various elms as the dominant species and as a part of stands composition have been analyzed by 10-year age classes for different origins (natural and planted). The proportion of the stand area of each 10-year age class was assessed for each set of subcompartments. Then the proportion of the stands’ area, which survives up to a certain age, was evaluated.

Results and Conclusions

In the Branch “Myrhorod forestry”, an area of natural stands with Ulmus sp. as the dominant species for 2010–2017, and the proportion of U. minor has significantly increased. The most dramatic decrease in the survival rate of all elm species of natural stands occurred in the VI age class and planted stands in the V age class. Respective natural and planted stands were formed in the 1960s and 1970s when the peak of DED occurred in many regions.

In the Branch “Myrhorod Forestry”, U. minor prefers moist fertile forest site conditions. U. laevis grows mainly in moist forest site conditions, U. pumila occurs in dry to wet habitats, U. glabra is present only in natural stands and absent in plantations. As part of stand composition, the same elm species grow in a wider range of forest site conditions than elms as the dominant species.

2 Figs., 8 Tables, 31 Refs.

Dynamics of the volumes of felling and forest renewal in Ukraine

I. M. Zhezhkun — 2024-06-27

Introduction

Since the beginning of the 21^st century, a positive trend in the dynamics of forest areas has been observed in EU countries. Thus, during 2000–2021, the increase in the area of forests in the EU amounted to approximately 8 million ha, and their standing volume increased by 31.2 % According to Global Forest Watch, during this period, Ukraine lost 1.26 million ha of forests, which is equivalent to 11 % decrease in forest cover. According to research by scientists of URIFFM, in recent decades, the total volume of forest renewal in Ukraine exceeds the area of legal clear-felling. Therefore, the study aimed to assess the trends in reforestation and afforestation in Ukraine over the past five years on a regional basis and compare the identified trends with the European ones.

Materials and Methods

The research used methods of deduction, quantitative methods of statistics, tabular and graphical modeling, economic analysis and synthesis, as well as methods of field forest research. The sources of information were data from the State Statistics Service of Ukraine (https://www.ukrstat.gov.ua/), the State Forest Resources Agency of Ukraine (https://forest.gov.ua/), legislative and regulatory documentation of Ukraine (https://zakon.rada.gov.ua/laws/), European statistics data (https://ec.europa.eu/eurostat/), international monitoring internet platforms (https://www.globalforestwatch.org/map/) and scientific publications on the research subject.

Results

It was found that reforestation in Ukraine is the main component of forest renewal in terms of volume making 83.9–95.5 %. During 2018–2020, the area of legal felling has been reduced in the whole country (by 2.0–12.5 % per year), as well as within its natural zones (Polissya (forest zone in Ukraine), Forest-Steppe, Steppe and Carpathians). In this period, according to statistical data, Ukraine's actual area of reforestation exceeded the total area of clear-felling and burned areas by 1.6–8.0 %. However, the areas of reforestation in Ukraine significantly decreased during martial law: by 25.9 % in 2022 and 24.2 % in 2023 compared to 2021. The share of clear-felling in the total volume of forest felling in Ukraine was calculated, which does not exceed 10 %. However, in the system of principal fellings, their proportion already reaches 74.5–85.0 %.

Conclusions

In recent years, according to statistics, both the total area of deforestation and the area of clear-felling have been decreasing in Ukraine, which is in line with the European trend of increasing forested areas. However, the volume of partial (gradual, selective, and combined) principal felling decreased. The data provided by the national statistics on the felling volume are incomplete due to the presence of illegal felling, the volume of which is recorded by the stocks of illegally obtained timber without taking into account the area of the plots. The volume of illegal logging has increased significantly in Ukraine since 2022 during the military actions. Also, under martial law, since 2022, there has been a certain decrease in the area of forest regeneration compared to previous years. At the same time, there has been a significant increase in the volume of afforestation activities as part of the implementation of the President of Ukraine’s initiative “Large-scale afforestation of Ukraine”.

2 Figs., 2 Tables, 23 Refs.

Forestry mensuration characteristics of pine stands in recreational and health-improving forests in the Left-Bank Ukraine

S. I. Musienko — 2024-06-27

Introduction

Many scientific studies in European and North American countries have focused great attention on the landscape and recreational characteristics of recreational and health-improving forests and their ecosystem services. In Ukraine, many studies have also been devoted to research on such forests. However, these studies were mainly aimed at assessing their potential to provide social services while insufficient attention has been paid to the mensuration variables and productivity analysis. Therefore, it is urgent to study the mensuration characteristics of pine stands in recreational and health-improving forests in different natural zones within the country. The present study aimed to identify the features of distribution, mensuration indicators, and productivity of pine stands in recreational and health-improving forests in the Left-Bank Ukraine depending on their functional purpose.

Materials and Methods

Mensuration characteristics of pine stands of recreational and health-improving forests in Left-Bank Ukraine were analyzed based on the data from the Forest Fund of Ukraine database of the Ukrderzhlisproekt Production Association (as of 2017). Studied forest plots are governed by the State Forest Resources Agency of Ukraine and are located in the Left-Bank Polissia, Left-Bank Forest-Steppe, and Left-Bank Steppe. The study covered forests within 11 administrative regions of Ukraine.

Results

The total area of pine stands of recreation and health-improving forests in the Left-Bank Ukraine is 196.6 thousand ha. By area and stock, planted stands predominate with 89.3% and 87.8%, respectively. The largest proportion of planted pine stands is 93.8% with 319 m³·ha^-1stock recorded in the Left-Bank Forest-Steppe. Their smallest proportion of 75.5% with a stock of 325 m³· ha-1 was found in the Left-Bank Polissia. By location, the largest part of pine stands (57.5% of the total area) is concentrated within the forestry part of green zone forests, and the smallest one (2.5%) is within the boundaries of cities, towns, and other settlements. The highest productivity (294 m³·ha^-1) was recorded for the pine stands within forest areas of green zones around settlements (forest park part). Almost half of the area of pine stands (49.7%) is in fresh oak-pine forest condition. Both in terms of area (65.2 %) and stock (73.9 %), middle-aged stands significantly prevail. Stands grow mainly by the 1st (44.0%) and 2nd (25.8%) site classes. Their relative density of stocking was 0.8 and 0.7, accounting for 72.1% of the total area.

Conclusions

In the recreation and health-improving forests in the Left Bank of Ukraine, a significant predominance of pine stands was noted within the green zones around the settlements. Their proportion was 88.1% of the total area. In terms of area and stock, planted stands significantly dominate, accounting for 89% and 88% respectively, so measures are needed to increase the proportion of forests of natural origin. Middle-aged stands significantly prevail in the region. The conditions in the Left-Bank Ukraine are generally favorable for the successful growth and development of pine forests and the effective performance of their recreational and health-improving functions. Evidence of this is the significant predominance of pine stands with a relative density of stocking of 0.7–0.8 and I and II site classes. The relative density of stocking of the studied pine stands in the region decreases after they reach 80 years of age, regardless of their location.

3 Figs., 7 Tables, 16 Refs.

Models for modal man-made pine stands characteristics dynamics in the Left-Bank Forest-Steppe of Ukraine

V. P. Pasternak — 2024-06-27

Introduction

In today’s environment, the development of regulatory and informational materials for evaluating and forecasting the growth of modal stands is relevant. This is particularly important considering zonal features that determine the degree of ecosystem function performance, allowing for a more objective evaluation of growth and the control of forestry measures' efficiency. Scots pine (Pinus sylvestris L.) is among the most resilient tree species. However, pine stands in the Left-Bank Forest-Steppe possess specific characteristics that necessitate detailed research.

The study aimed to reveal the growth and productivity features of modal man-made pine stands in the Left-Bank Forest-Steppe of Ukraine.

Materials and Methods

To develop growth tables, information from the compartment database “Forest Fund of Ukraine” of the Production Association “Ukrderzhlisproekt” (for Forest-Steppe parts of Kharkiv and Sumy regions), data from observations at 33 sample plots in pine stands for State Specialized Forest Enterprise (SSFE) “Forests of Ukraine”, Branches “Lebedyn Forestry”, “Konotop Forestry”, “Okhtyrka Forestry”, “Trostyanets Forestry” (Sumy region), “Zhovtneve Forestry”, “Chuguyevo-Babachansk Forestry”, State Enterprises “Vovchansk Forestry” and “Skrypayivske Educational and Research Forestry” (Kharkiv region), and 13 permanent monitoring plots in SSFE «Forests of Ukraine», Branches “Zhovtneve Forestry”, “Skrypayivske Educational and Research Forestry”, NNP “Slobozhanskyy” (Kharkiv region) were used. Additionally, a sample plot located in the SSFE “Forests of Ukraine”, Branch “Guty Forestry” (Kharkiv region) was used, where 12 model trees were felled and measured. The sites were predominately located in fresh poor (A₂) and relatively poor (B₂) forest site conditions, as well as fresh relatively fertile (C₂) site conditions.

Average tree heights and growing stocks were approximated using the Mitscherlich function. The transition from relative to absolute values was executed based on the basic height values of the modified scale of M.M. Orlov for 80-year-old stands of seed origin. An allometric function was employed to model average diameter, factoring in age and stand height.

Results

The research established patterns in the dynamics of the main forest evaluation indicators. The height growth of man-made pine stands occurs within one site index class of the general site index scale. However, at a younger age, growth tends to slow down. Stands in the Left-Bank Forest-Steppe exhibit slightly more intensive height growth at 20–30 years of age, resulting in larger diameters and growing stocks compared to modal pine stands in Prydniprovskyi Northern Steppe according to V.M. Lovynska.

Conclusions

The developed regional growth tables objectively characterize dynamics, considering regional growth features of modal pine stands in the Left-Bank Forest-Steppe of Ukraine. These tables can serve as a basis for addressing scientific and practical forestry tasks.

Modal man-made pine stands demonstrate relatively high productivity. The height growth of such stands occurs within one site class of the general site scale, with growth slowing down at younger ages, particularly in fresh poor conditions (A₂). Quantitative maturity of modal man-made pine stands in A₂, B₂ and C₂ is determined by the average change in stock occurring at 55, 45 and 40 years old, respectively. The productivity of modal man-made pine stands in the Left-Bank Forest-Steppe surpasses that of the Prydniprovskyi Northern Steppe of Ukraine, likely due to better moisture availability.

2 Figs., 3 Tables, 28 Refs.

Success of felling and reforestation in weakened pine forests in the fresh relatively infertile pine site type in Klavdiievo Forest Research Station

M. P. Savushchyk — 2024-06-27

Introduction

Research on the success of natural pine regeneration in various forest site conditions in Kyiv Polissia has been carried out for many decades. The long-term studies of the natural regeneration of pine stands have not revealed a universal approach even within the same forest site type region. The influence of many variable factors on natural regeneration explains this fact. Therefore, the regularities found in one region's forests cannot be transferred to another, which requires further systematic research. The study aimed to assess the stand state dynamics and the success of different methods of pine stand regeneration in the case of gradual and continuous felling in the fresh oak-pine forest site type in Kyiv Polissya.

Materials and Methods

The object of research was the experimental and production plot established in 2008. Continuous sanitary felling was planned in the subcompartment. A part of the plot (3 hectares in area) was used for research. The two-section experiment was established in a weakened uneven-aged pine stand, which grows in a fresh oak-pine forest site condition. In the first section of 2 ha of the experiment, continuous felling was carried out and seed trees were left, while in the second section of 1 ha, the first stage of evenly-gradual felling was applied.

Field data were collected and processed based on generally accepted forestry and mensuration.

Results

According to the survey of the experimental site in the autumn of 2023, the pine trees in the section of continuous felling intensively grew. An average height was 7.1 m and an average diameter of 7.2 cm corresponding to 1a site class. The stand was fully stocked (the average relative stocking density was 0.8). It was uneven and needed to be cleaned. The forest stand was partially damaged because of hostilities.

In the gradual felling section as of 2008, 486 trees were growing. The first stage of gradual felling was high intensity (70% of the stock). After that, 129 trees were left in the section, of which 124 were pines and 5 oaks. A drastic change in the growth conditions of the abandoned part of the stand caused the death of trees. The most significant decline occurred during the first five years after the felling: 46% of the initial number of left trees died.

After the felling was completed, measures were taken to promote natural regeneration. In the spring of 2009, the soil was partially plowed up and in 2010 pine seeds were additionally sowed. The natural regeneration of the section was recorded in 2011, 2013, 2015 and 2023. As of autumn 2023, the success of natural regeneration according to the scale developed in URIFFM was evaluated as “insufficient”. The amount of pine undergrowth was less than the standard specified in the Rules of Final Felling for the final stage of evenly gradual felling.

Conclusions

The results of long-term research at the experimental and production site show that in a fresh oak-pine forest site condition in State Enterprise “Klavdiievo Forest Research Station” evenly-gradual felling in weakened pine stands does not ensure successful forest regeneration according to the standards of the current Rules of Final Felling in the Forests of Ukraine, even together with soil mineralization and additional sowing of seeds as measures to promote natural regeneration. However, forest sowing in a clear-cut area has been successful. Therefore, it can be assumed that evenly-gradual felling could be applied followed by combined regeneration. However, when planning additional research, it should be considered that in weakened pine stands, with a high intensity of the first stage of evenly gradual felling, the intensive tree decline will occur in the left part of the stand during the first years.

4 Figs., 11 Refs.

Current trends in wood market functioning in Ukraine

I. M. Zhezhkun — 2024-06-27

Introduction

The 2022 military aggression against Ukraine harmed the socio-economic conditions in the country and has significantly changed the trends of its development. The negative economic trends in the forestry of Ukraine caused by the military operations are intensifying due to the ongoing reform of the state sector management of the industry starting in 2021 with the merging of state-owned forestry enterprises in the State Specialized Forest Enterprise (SFE) “Forests of Ukraine” with the corresponding centralization of management and economic functions. Along with the difficulties of the transformational period in the Ukrainian forestry industry, there are also economic problems with the mandatory sale of round timber exclusively through electronic stock trading. The study of modern trends in the wood market of Ukraine, as well as the prospects for stabilization and improvement of its functioning, is particularly relevant considering the institutional transformations in the Ukrainian forestry industry in 2021–2023 and war related force majeure circumstances in the country’s economy. Also, in addition to modern positioning, an important economic task in any industry is to determine its future position according to the scenario approach. Extrapolation forecast is one of the methods that helps to establish potential production volumes of certain product types in the future. Therefore, the study aims to investigate the dynamics and structure of roundwood harvesting indicators in Ukraine compared to the pre-war period in 2021 and potentially possible parameters for the further use of the obtained results for scenario forecasting of the domestic wood market.

Materials and Methods

Quantitative methods of statistics, grouping, comparison, tabular and graphic modeling, economic analysis and synthesis, and economic-mathematical methods of extrapolation linear forecasting have been used in the research. Extrapolation linear forecasting was carried out using standard Microsoft Office Excel 2003 software ("LINEST" and "TREND" functions). The input information for the analysis was open information from the State Statistics Service of Ukraine (website https://www.ukrstat.gov.ua/), SFE “Forests of Ukraine” (website https://e-forest.gov.ua/), State Forest Resources Agency of Ukraine (website https://forest.gov.ua/), legislative and regulatory documentation of Ukraine and scientific publications on the research subject.

Results

The negative impact of military operations on the wood market of Ukraine has been established. In 2022 the volume of wood harvesting decreased by 9.7% (or by 1,715.1 thousand m³) and roundwood by 9.5% (or by 1,581.8 thousand m³) compared to the previous year. In 2022, the wood market in Ukraine experienced the largest negative trends due to a decrease in the supply of coniferous wood (by 18.0%, or by 1,768.2 thousand m³). A significant decrease in the volume of roundwood harvesting occurred in 2022 compared to 2021 within three natural zones of Ukraine (except for the Carpathians): by 37.9% in the Steppe, by 11.3% in the Forest-Steppe, and by 9.6% in Polissia. The decisive influence of SFE “Forests of Ukraine” on the volume of wood supply in the domestic market in 2023–2024 was revealed.

An increase in the production of firewood (instead of industrial wood) during felling is foreseen in 2024 by the assortment plan of the SFE “Forests of Ukraine”. This indicates the deterioration of the wood marketability planned for felling and hence the biological stability and health condition of the Ukrainian forests. The stability of the assortment structure of round timber by quality classes for all species groups in the SFE “Forests of Ukraine” during 2023–2024 was established, with relatively higher quality of softwood broadleaved species and relatively worse quality of hardwood species. It was determined that the number of business entities in Ukraine in the wood harvesting industry decreased by 9.3% in 2022, in woodworking industry by 14.0%, in the furniture industry by 12.9%, and in the production of paper pulp, paper and cardboard by 15.1%.

Conclusions

The negative trends of 2022–2024 regarding the wood harvesting and consumption in Ukraine will continue in the next few years due to ongoing military operations. Forecasted by linear extrapolation, the volume of roundwood harvesting exceeds the actual indicators in 2021–2022 by 16.5% and 25.7%, respectively. These volumes are a reserve if the economy would function in conditions “without war”.

8 Figs., 3 Tables, 21 Refs.

First data on box-tree moth seasonal development in the green areas in Zhytomyr

O. Yu. Andreieva — 2024-06-27

Introduction

Box-tree moth Cydalima perspectalis (Walker, 1859) (Lepidoptera: Crambidae) originates from east Asia. This pest was revealed in Europe in 2006 and is now present in most of the regions of Ukraine. In its range, the box-tree moth can develop in two to five generations per year, causing the weakening and mortality of Buxus L., particularly Buxus sempervirens L.

The analysis of publications shows the variation in the timing of box-tree moth development and the number of generations. Thus, in some regions of Asia, the pest has up to five generations, in the south of Romania – three, in Switzerland and Canada – two. The development of individual generations often overlaps, and it is difficult to determine their exact number. Some data on the duration of individual stages at a constant temperature were obtained during laboratory rearing of the box-tree moth and used for modeling its development and spread. We started detailed studies of this pest in Zhytomyr in the spring of 2022, when more than 10 % of boxwood bushes were inhabited, and the density of caterpillars was from 7 to 20 specimens per bush.

This research aimed to identify the features of box-tree moth seasonal development in the green areas of Zhytomyr to determine the optimal terms for monitoring the spread and development of this pest and measures for its control.

Materials and Methods

Our research was carried out in the Botanical Garden of the Polissky National University (Zhytomyr, 50°15?09? N; 28°42?00? E). The phenology of the box-tree moth was studied during 2022, 2023 and the first half of 2024 by inspecting box-tree plants with an interval of two weeks before the beginning of the growing season and with an interval of one week during the growing season. On each date, the stages of the pest were assessed by examining box-tree branches (10 branches 10 cm long on each of the 10 model plants). In particular, the dates of caterpillars’ hibernation, the beginning feeding after wintering, their pupation, moths swarming, eggs, caterpillars, and pupae in the next generations were recorded.

The caterpillars’ instar was estimated by head capsule width. Data from the Zhytomyr weather station were used to calculate the average air temperature for a month and during the individual stages of the box-tree moth in 2022–2024.

Results and Conclusions

The box-tree moth develops in two complete generations in the Botanical Garden of the Polissky National University. Caterpillars of the third generation, starting from September, slow down their development and enter diapause in the 3rd–4th instars. The end of the first period of the imago swarming (from the third decade of June to the third decade of July) is close to the beginning of the second period of the imago swarming (from the first decade of August to the first decade of September). The possibility of overlapping development of individuals of two generations indicates the threat of new box-tree plants being populated and damaged during most of the summer. The termination of caterpillar diapause and resumption of feeding in the spring occurs approximately after the date of a stable temperature transition over 10 °C. Inspection of box plants and their protection, if necessary, must be carried out at this time. The obtained data on the box-tree moth seasonal development in its secondary range are of theoretical importance for clarifying the trends in the seasonal cycles of multivoltine phytophagous insects under climate change.

5 Figs., 23 Refs.

Biological features and trophic specialization of the acorn moth Blastobasis glandulella (Riley, 1871) (Blastobasidae) in the Western Podillia

I. M. Sokolova — 2024-06-27

Introduction

Blastobasis glandulella (Riley, 1871) (Blastobasidae (Meyrick, 1894)) originates from the eastern United States and southern Canada. Larvae develop in acorns of different species of Quercus L. and fruits of Castanea Mill. and Carya Nutt. B. glandulella has been known in Europe since the early 80s and has spread to 16 countries. It was first identified in Ukraine in 2009 in Transcarpathia. The phenology of B. glandulella has not yet been investigated. In 2022, researchers of the Department of Entomology, Phytopathology, and Physiology in Ukrainian Research Institute of Forestry and Forest Melioration analyzed acorns from various regions of Ukraine. They found the pest in the acorns collected in Kyiv, Cherkasy, Poltava, Khmelnytskyi, and Ternopil regions. Preliminary analysis of the material showed that in the east of the Ternopil region and the southwest of Khmelnytskyi region, the acorn moth formed stable populations and damaged many acorns. Therefore, the study of this alien species was carried out in Western Podillia.

This research aimed to clarify the specifics of acorn moth development and its host plants in Western Podillia.

Materials and Methods

Our research was carried out in the forest stands and in the laboratory. Phenological observations and collection of fruits for subsequent analysis and rearing to adults were carried out at eight locations in the Kamianets-Podilskyi district of Khmelnytskyi region and Chortkivskyi district of Ternopil region. Acorns and fruits of Aesculus sp. and Juglans sp. were collected from late fall to early spring. In the laboratory, the entrance and exit holes in fruits were recorded. Then the fruits were cut to record larvae, pupae, excrement, etc. A total of 2,240 acorns of various oak species, 260 horse chestnut fruits, and 250 nuts were analyzed.

A method for acorn moths rearing from larvae found in fruits has been developed and tested. To study the moth phenology, in the field, from March to October at least 50 acorns were collected and analyzed from one location.

The pupation and moth emergence dates were recorded in natural conditions. To determine the dates of egg hatching, the fruits were collected from the beginning of July.

Results and Conclusions

It was found that, besides acorns of various oak species (Quercus robur L., Q. rubra L., Q. castaneifolia C. A. Mey), caterpillars of the acorn moth develop in the fruits of Aesculus hippocastanum L., A. parviflora Walt., A. glabra Willd. and some Juglans sp. (Juglans cinerea L. and J. regia L.). A caterpillar has a long lifespan, overwinters inside the fruits, and completely consumes their cotyledons. As one acorn (fruit) is consumed, the caterpillar crawls to another, damaging several fruits before pupation, which lose their viability. The larvae pupate inside or outside the fruit, or on the forest floor, from April to mid-September. B. glandulella prevents seed regeneration of forests, obtaining oak, walnut, and horse chestnut seeds, and planting material for forest and urban stands.

10 Figs., 1 Table, 18 Refs.

Litter as a marker of anthropotechnogenic changes in the pine forests in the plain part of Ukraine

V. P. Voron — 2024-06-27

Introduction

Rational forest use should be based on a comprehensive investigation of the mechanisms of the environmental factors that influence forest stands. The severity of the destructive process in the forest litter depends on precipitation and litter decomposition activity. Under certain conditions, the thickness and structure of forest litter may contribute to fire emergence. As litter is the main component of combustible materials in the forest ecosystem, its mass and condition may determine fire development. The research aimed to reveal the features of changes in the precipitation-litter link in pine forests under anthropogenic influence.

Materials and Methods

The study of the forest litter formation under aerotechnogenic pollution was carried out on permanent sample plots in the industrial zones: Rivne Industrial Joint Stock Company “Azot” (RVAT “Azot”) and Lysychansk-Rubizhne-Siverodonetsk Industrial Agglomeration with dominance in emissions of SO₂, NO_x, NH₃ and Zmiiv Thermal Power Plant, the emissions of which are dominated by oxides of sulfur, nitrogen and ash with a high content of heavy metals. The floor and litter stocks were assessed in the pine forests in the green zone of Kharkiv, in the ecological series of sample plots according to the stages of recreational digressions.

Results

Under industrial pollution, markers of change in the forest litter are associated with the chemical influence of pollutants. The content of pollutants increases from the top to the bottom layer of litter. These trends are particularly pronounced for heavy metals. The total stock of heavy metals in the litter in the industrial zone was 3.4–5.5 times higher than in the control area. As a result of pollution, the litter mass increases, so the rate of phytodetritus mineralization is an important indicator of technogenic influence. It was found that the total time for the formation of the mortmass in the industrial zone was 0.9–3.0 years longer than in the control plot.

Changes in forest litter under recreational influence are associated with mechanical pressure. As a result of the recreational load, the slow biocycle in the precipitation-litter chain, which is typical for pine forests, is further inhibited. In all layers of litter mineralization, the accumulation of mortmass dominates over decomposition.

Conclusions

The total time of forest floor formation was 0.9–3.0 years longer in the industrial zone than in the control zone. The content of pollutants, in particular S and N, increased from the upper to the lower litter layer. The Cr content in the H layer of the litter was 12–14 times higher than in the L layer, Cu content was 4–19 times higher, Zn content – 7–11 times, Sr content – 8–13 times, Pb content – 13–18 times. In general, the stock of heavy metals in the litter in the industrial zone was 3.4–5.5 times higher than in undisturbed forests.
Pine stands in relatively poor forest site conditions accumulate higher litter stocks than in poor site conditions: in 60-year-old stands, it was 35,500 kg ha^-1 in relatively poor site conditions and 70,300 kg ha^-1in poor site conditions.

9 Tables, 20 Refs.

Assessment of losses of carbon stored in the aboveground biomass of pine stands damaged by surface fires in the Polissia and Left-Bank Forest-Steppe

I. M. Koval — 2024-06-27

Introduction

Forest vegetation stores carbon and is the main carbon reservoir on the planet. Fires affect carbon stocks and the carbon cycle. The main causes of fires are anthropogenic factors. The impact of Russia's military aggression against Ukraine resulted in damage to 30% of the country's forest area. The capacity of forestry enterprises to protect forests and control fires has diminished under martial law. Under these conditions, studies on carbon loss in fire-damaged stands are extremely relevant.

The study aimed to reveal the impact of surface fires of intensity on carbon sequestration in the biomass of pine stands in forest and forest-steppe natural zones.

Materials and Methods

The study was conducted in the fire-damaged pine stands growing in Polissia and the Left-Bank Forest-Steppe in Ukraine.

The first object of the research was a middle-aged pure pine stand in the Nemovytsky subunit of Branch “Sarny Forestry” of the State Specialized Forest Enterprise «Forests of Ukraine». The forest site conditions type is moist relatively infertile (B₃) on loamy soils (Polissia). The forest was damaged by surface fire in the spring of 2012. The surface fire had medium intensity, as evidenced by the fire scorch height.

The second object of the study was a middle-aged pure pine stand in the Babai subunit of the Branch “Zhovtneve Forestry” of the SFE «Forests of Ukraine», which was damaged by fire in the spring of 2011. The stand grows on sandy turf podzolized soils. The forest site conditions type is fresh relatively infertile one (B₂). Three permanent research plots with different levels of fire damage have been laid out.

To estimate the biomass stock before the fire, the ‘Norms for assessment of above-ground biomass components of trees of the main forest-forming species of Ukraine’ were used. Calculations were made considering stem thickness degrees. The volumes of the sequestered carbon were calculated using two main indicators: the absolutely dry stand biomass and the percentage of carbon content (or its volume) in one tonne of the absolutely dry organic matter.

Results

Post-fire carbon losses due to tree mortality depend primarily on the fire intensity, damage type, and fire resistance of the stands (i.e. fire resistance at the level of the trees in the stand). In Polissia, 14 trees died (14%) one year after the fire in 2013 and 42 trees (58%) died three years after the fire in 2015. The loss of stored carbon in aboveground biomass was 6% (4.87 t·ha^-1) one year after the fire and 61% (30.4 t·ha^-1) three years after the fire. In the Left-Bank Forest-Steppe, the loss of stored carbon in the aboveground biomass of middle-aged pine stands damaged by a fire with a fire scorch height of 0.61 cm was 3% (0.021 t·ha^-1) three years after the fire, in 2014. The loss was 8% (6.37 t·ha^-1) for the stand with a fire scorch height of 1.76 cm and 30% (29.2 t ha^-1) for the most damaged pine stand with an average fire scorch height of 3.76 cm.

Conclusions

Post-fire carbon losses in aboveground biomass due to tree mortality depend primarily on fire intensity and damage type, the length of the post-fire period, and the fire resistance of the stand (fire resistance at the level of the trees in the stand). The preliminary data obtained indicate that in Polissia (in moist relatively infertile forest site type) a higher level of mortality was detected at a lower fire intensity than in Left-Bank Forest-Steppe (in fresh relatively infertile forest site type). Accordingly, the largest losses of stored carbon were found in fire-damaged pine stands under moister conditions in Polissia compared to pine forests in Left Bank Forest-Steppe in dryer forest site conditions.

3 Figs., 4 Tables, 26 Refs.