Tree Diameter Research Articles

Carbon stock of Agoro Agu Central Forest reserve, in Lamwo district, Northern Uganda

Terrestrial ecosystems such as forest landscapes provide critical ecosystem services such as carbon sequestration, fundamental to people, society and the global climate change discourse. Just like moist forest, dry Afromontane forests too present a high carbon sequestration potential. However, Uganda has since not undertaken carbon stock inventories for these conservation areas, especially with dry Afromontane forests like Agoro-agu central forest reserve (CFR). So, their potential to capture and store carbon is yet to be understood in Uganda. This study was carried out to estimate carbon stock of Agoro-agu CFR, for its potential in climate change mitigation. A stratified sampling design was used, where 65 sample plots were established. Nested, fixed area circular sample plots with sub-plots of varying radii for tree height, diameter measurements and soil sampling, were used. The mean total carbon stock of Agoro-agu CFR was estimated at 606.7 Mg C ha−1, for which 409, 72, 124 and 0.24 Mg C ha−1 was stored as above ground carbon, below ground carbon, soil organic carbon and carbon in litter herbs and grass respectively. The study illustrates the carbon sequestration potential of the forest reserve for any results-based payment projects for climate change mitigation. This is mainly due to the interventions through collaborative forest management arrangements and the pro-poor reducing emissions from Deforestation and forest Degradation (REDD+) pilot project in the landscape. This however, calls for more multi-stakeholders’ collaboration from direct resource users to national level to enhance forest conservation and reduce forest degradation for sustainable resource benefits and other ecosystem services.

Condition of pine and larch forests adjacent to the reservoir within the Sayano-Shushensky Nature Reserve

Forests cover 60% of the Sayano-Shushensky Nature Reserve, 48% of which are larch and pine stands. The purpose of the research was to assess condition of Larix sibirica Ledeb. and Pinus sylvestris L. forests adjacent to the reservoir within the reserve. We conducted forest pathological inspection (for each species on four research plots), an integral assessment of the stands condition, macroscopic diagnostics and disease manifestations indicators estimation and studied model trees affected by xylophagous insects. Studied stands ranged from sustainable to ones with disturbed sustainability and their health status ranged from healthy to varying degrees of weakening. One of the main factors weakening forest stands were ground fires, leading to increased mortality of small-diameter trees that are less resistant to heat stress (most typical of P. sylvestris). Medium and large diameter trees post-fire mortality in L. sibirica forest stands was due to the Zeiraphera griseana feeding, and in relatively flat coastal areas due to repeating flooding. The presence of groups of trees dying from the top down were observed in pine forests growing on thin soils most likely due to an imbalance between the amount of required and available soil moisture. Diseases were not common and did not have a significant impact on the forest stands. Potentially harmful are the following diseases: in larch forests - European larch canker (pathogen - Lachnellula willkommii), in pine forests - Scots pine blister rust (pathogen - Cronartium pini). Xylophagous insects (dominated by Ips acuminatus) had an increased abundance and fed on dying trees in pine forests weakened after fires.

Modeling compatible taper and stem volume of pure Scots pine stands in Northeastern Turkey

Compatible taper and volume equations for pure and natural Scots pine stands in the northeastern part of Turkey (Ardahan Province) were developed using a nonlinear mixed-effects modeling approach. Experimental data were obtained from 137 felled sample trees in different diameter and height classes. The most successful model (Jiang et al. 2005) explained 98.3% of the variance in stem diameter estimation and the RMSE, ME, MAE, AIC and BIC value obtained using this model were 1.955 cm, 0.043 cm, 1.300 cm, 9783.8 and 9812.6, respectively. Considering the criterion values of AIC, BIC and -2LnL, the model with random-effects in two parameters (b1 and b3) was the most successful for Scots pine. While the mixed model including random parameters did not completely solved the problem of the autocorrelation of errors in this study, the use of the autoregressive error structure AR(1) eliminated the autocorrelation in the residuals. In addition, the best estimation results among 20 different calibration options were obtained using the option of measuring two tree diameters at d1.30 and d5.30 with validation data. The most successful model explained 99.18% of the total variance in stem volume estimation in Scots pine.

Estimation of Aboveground Biomass of Individual Trees by Backpack LiDAR Based on Parameter-Optimized Quantitative Structural Models (AdQSM)

Forest aboveground biomass (AGB) plays a key role in assessing forest productivity. In this study, we extracted individual tree structural parameters using backpack LiDAR, assessed their accuracy using terrestrial laser scanning (TLS) data and field measurements as reference values, and reconstructed 3D models of trees based on parameter-optimized quantitative structural models (AdQSM). The individual tree AGB was estimated based on individual tree volumes obtained from the tree model reconstruction, combined with the basic wood density values of specific tree species. In addition, the AGB calculated using the allometric biomass models was validated to explore the feasibility of nondestructive estimation of individual tree AGB by backpack LiDAR. We found that (1) the backpack LiDAR point cloud extracted individual tree diameter at breast height (DBH) with high accuracy. In contrast, the accuracy of the tree height extraction was low; (2) the optimal parameter values of the AdQSM reconstruction models for Larix gmelinii and Betula platyphylla were HS = 0.4 m and HS = 0.6 m, respectively; (3) the individual tree AGB estimated based on the backpack LiDAR and AdQSM fit well with the reference values. Our study confirms that backpack LiDAR can nondestructively estimate individual tree AGB, which can provide a reliable basis for further forest resource management and carbon stock estimation.

Allometric Growth of Common Urban Tree Species in Qingdao City of Eastern China

Allometric growth equations help to describe the correlation between the variables of tree biological characteristics (e.g., diameter and height, diameter and canopy width) and estimate tree dynamics at a given tree dimension. Allometric models of common tree species within urban forests are also important to relate ecosystem services to common urban tree measurements such as stem diameter. In this study, allometric growth models were developed for common tree species used for urban greening on the streets of seven municipal districts in Qingdao city of eastern China. A sampling survey was constructed on an urban–rural gradient to obtain the data of tree diameter, crown width, height to live crown base, and tree height. From these measurements, the crown volume and crown projection area of tree species were calculated. The allometric relationship between two variables was established using quantile regression models (95%, 50%, and 5%) to explore its correlation and the influence of tree species characteristics on urban tree allometry. Our results showed that the correlation of allometric growth of different tree species varied largely due to their own characteristics, and the allometric growth of the same tree species was significantly different as well under the fitting of different quantiles. We found that the relationship between crown width and diameter was stronger than that between tree height and diameter. Moreover, the allometric relationship between crown projection area–diameter and crown width–diameter showed similar fitting. The allometric relationship analysis provide theoretical models and a way to use common field data to support urban forestry management and for the subsequent evaluation and prediction of tree functions and ecosystem services.

Evaluation of the Occurrence of Hollows in Trees in Managed Forest in the Eastern Brazilian Amazon

Abstract This study proposed to generate information related to the abundance and the structural characteristics of hollows at the tree and species levels in an area of managed forest in the Amazon. A database was used that was composed of 29,899 trees from thirty-eight species that were inventoried, harvested, and measured in ten annual production units that were managed between 2008 and 2017 in the Tapajós National Forest, state of Pará, Brazil. The data was tabulated and reported in absolute and percentage values. Contingency tables were created to identify patterns of occurrence of hollows in commercial stems. A total of 24% of the harvested trees had hollows in at least one section of the commercial stem, and species had different propensities for hollow occurrence. It was found that the larger the tree diameter the greater the possibility for occurrence of hollows, and these hollows were proportionally larger. Most of the hollows in harvested trees were small. Patterns of occurrence in commercial stem hollows were observed, and these were dependent on tree species and size. Most trees had hollows distributed along the entire stem or only at the base of the stem. Study Implications: The presence of hollows in managed native forest trees in the Amazon depends on the species, and trees with larger diameters have a greater probability of having hollows. Furthermore, trees with larger diameters have hollows that have larger diameters, lengths, and volumes. Commercial trees have different patterns of hollows along the stem, and these patterns are dependent on tree species and size. The results of this study will contribute to management of trees with hollows in the Amazon Forest as well as to serve as a base for future studies related to this theme.

Number Preference as a Source of Measurement Error in the U.S. National Forest Inventory

Number preference, i.e., the human tendency to gravitate toward or away from specific numbers, is a potential source of measurement error in forest inventory. Identifying its presence is an important step to ensure unbiased results. This study evaluated U.S. national forest inventory data for number preference and identified factors that influence the proportion of tree cull volume, tree diameter, tree height, and seedling count observations ending with the digit zero or five (ED0,5) and seedling count observations that were multiples of four (M4). Two-sided hypothesis tests determined that ED0,5 occurred significantly more frequently than expected by chance for all metrics tested, though not in every inventory region of the country nor to the same degree. Consistently, tree-level ED0,5 was more likely when metrics were estimated visually rather than measured instrumentally. Logistic regression indicated that the effect of species class, species type, tree status, treetop status, and stem size on tree-level ED0,5 and the effect of plot-level water depth on seedling count ED0,5 also varied by region. Though the effect was small, findings suggest that some inventory regions may be employing an approved multiplicative shortcut that results in a greater-than-expected proportion of M4 observations among seedling counts.

Numerical Analysis of a TCR Adaptive to Different Tree Diameters for Unstructured Forest Environment: A TCR of Variable Diameter with Different Tree Diameters

This paper proposes the optimal design and simulation analysis of a robot for tree-climbing, which has the ability to climb up the tree trunk to adapt to different tree diameter changes. In an unstructured forest environment, considering that the Tree-Climbing Robot (TCR) may collide with branches, reducing the success rate of tree climbing, the mechanical structure and movement strategy to avoid branches are predesigned. The presented TCR mimics several design principles that have been adapted to arboreal animals, including claw-hand grasping and climbing gait movements, and is optimally designed to achieve high manoeuvrability on irregularly shaped trees. Based on the D-H parameterization method, the kinematics model of the TCR is developed and its kinematic equations are solved. The accuracy of the kinematic equations is verified by MATLAB, and the reachable area of the working space of the manipulator of the TCR is determined. Using ADAMS to analyse the kinematics and dynamics of the climbing process of the TCR, the rationality of the gait planning of the robot is verified, and the time-varying characteristic curves of each physical quantity of each structural joint are derived and further simulated through numerical analysis, the results of which will profoundly validate the technical feasibility and design innovation of this presented TCR.

Evaluating effectiveness of girdle-herbicide containment of below-ground spread of oak wilt (Bretziella fagacearum)

Oaks (Quercus spp) are one of the most important sources of timber, mast for wildlife, and ecosystem services across the eastern US. Increasingly, this genus is at risk from diseases including oak wilt, which is one of the most serious threats to oaks, caused by the fungus, Bretziella fagacearum. The upper Midwest has over 5 million ha of oak forests, much of which is on rocky glaciated soils where traditional methods of containing below-ground spread of oak wilt (e.g., vibratory plow lines) are not feasible. We evaluated an alternative containment method of girdling and herbicide (GH) of oak wilt infected trees as well as neighboring oak trees likely connected via root grafts. Our results demonstrated that GH was effective at controlling below-ground spread of oak wilt (overall success rate: 55 %). Best control was achieved when infection centers were small (≤4 newly infected trees), where GH was 81 % effective at containing oak wilt. Containment was only 29 % in larger infection centers (≥5 newly infected trees). The best predictor of success was the number of newly infected trees (p = 0.02) even when considering other factors that could dictate the size of infection centers (e.g., diameter of trees, or number of neighboring trees treated). Our results illustrate the importance of early and rapid management of oak wilt infections and offer a starting place for continued improvement of the GH methodology.

Design-based spatial interpolation with data driven selection of the smoothing parameter

In the inverse distance weighting interpolation the interpolated, value is a weighted mean of the sampled values, with weights decreasing with the distances. The most widely adopted class of distance functions is the class of negative powers of order alpha and the appropriate choice of the smoothing parameter alpha is a crucial issue. In this paper, we give sufficient conditions for the design-based consistency of the inverse distance weighting interpolator when alpha is selected by cross-validation techniques, and a pseudo-population bootstrap approach is introduced to estimate the accuracy of the resulting interpolator. A simulation study is performed to empirically confirm the theoritical findings and to investigate the finite-sample properties of the interpolator obtained using leave-one-out cross-validation. Moreover, a comparison with the nearest neighbor interpolator, which is the limiting case for alpha =infty , is performed. Finally, the estimation of the surface of the Shannon diversity index of tree diameter at breast height in the experimental watershed of Bonis forest (Southern Italy) is described.

Forest carbon stock and biomass estimation in West Central India using two allometric models

The west central Indian forest ecosystems strongly contribute to livelihood of local human communities as well as climate change mitigation. However, due to the lack of accurate biomass equations and predictive tools, the contribution of these forests towards carbon stock and sequestration remains poorly recognized. At present due to some developmental and mining activities these forests face huge anthropogenic pressure.Therefore, the objective of the present study was to estimate the biomass and carbon stock of forest tree species of west central India to provide baseline information. It will also be useful for measuring the changes after the intervention as well as for future management and conservation.The non-destructive allometric equation approach was adopted to estimate the biomass, carbon stock and carbon dioxide equivalent from total 28 plots of 0.1 ha at seven sites of dry deciduous forests of west central India. In the present study, the results of biomass and carbon stock were calculated by employing two different allometric models.The model with tree diameter and wood specific gravity gave higher estimations of total plant biomass (123.39 – 65.86 Mg ha−1) and carbon stock (58.61—31.28 Mg ha−1) as compared with model having only tree diameter (108.84 – 55.91 Mg ha−1) and (51.70 -26.55 Mg ha−1), respectively.We conclude that the allometric model with tree diameter and wood specific gravity was found best suited for these forests. The results also showed the positive relation between tree diversity, basal area and aboveground biomass and carbon stock.

Diameter, height and species of 42 million trees in three European landscapes generated from field data and airborne laser scanning data

Ecology and forestry sciences are using an increasing amount of data to address a wide variety of technical and research questions at the local, continental and global scales. However, one type of data remains rare: fine-grain descriptions of large landscapes. Yet, this type of data could help address the scaling issues in ecology and could prove useful for testing forest management strategies and accurately predicting the dynamics of ecosystem services. Here we present three datasets describing three large European landscapes in France, Poland and Slovenia down to the tree level. Tree diameter, height and species data were generated combining field data, vegetation maps and airborne laser scanning (ALS) data. Together, these landscapes cover more than 100~000~ha and consist of more than 42 million trees of 51 different species. Alongside the data, we provide here a simple method to produce high-resolution descriptions of large landscapes using increasingly available data: inventory and ALS data. We evaluated the overall reliability of our workflow by comparing the stands dominant heights measured by ALS to those calculated from the trees we generated. Overall, the landscapes we generated are in good agreement with the landscapes they aim to reproduce.

Relationships Among Biomass, Carbon, and Microfibril Angle in Young <i>Shorea</i> spp. (Dipterocarpaceae) in Indonesia

Indonesia, particularly the island of Java, is dominated by a number of Shorea tree species (Dipterocarpaceae). Trees of the genus have been utilized for various practices, and they play a fundamental role in managing the stability of tropical forests. This study was carried out to understand the relationships between biomass and microfibril angle in Shorea spp. growing in West Java, where Shorea spp., are abundant. A total of 35 young trees belonging to 5 species were studied. The average age of these trees was 9 years, but in general there was a wide variation in tree diameter and total height. On average, biomass was the highest in S. leprosura and the lowest in S. palembanica. The lowest average microfibril angles (MFAs) were found in S. leprosura and S. mecistopteryx. The regression relationship between biomass and diameter was strong with an R2 value of 0.85, while the strength of the relationship between MFA and diameter was weaker (R2 = 0.195). In general, the MFA degree decreased with increased biomass accumulation Shorea species, which affects tree resistance to environmental variables and competitiveness in Indonesian tropical forests.

Importance of conserving large and old trees to continuity of tree-related microhabitats.

Protecting structural features, such as tree-related microhabitats (TreMs), is a cost-effective tool crucial for biodiversity conservation applicable to large forested landscapes. Although the development of TreMs is influenced by tree diameter, species, and vitality, the relationships between tree age and TreM profile remain poorly understood. Using a tree-ring-based approach and a large data set of 8038 trees, we modeled the effects of tree age, diameter, and site characteristics on TreM richness and occurrence across some of the most intact primary temperate forests in Europe, including mixed beech and spruce forests. We observed an overall increase in TreM richness on old and large trees in both forest types. The occurrence of specific TreM groups was variably related to tree age and diameter, but some TreM groups (e.g., epiphytes) had a stronger positive relationship with tree species and elevation. Although many TreM groups were positively associated with tree age and diameter, only two TreM groups in spruce stands reacted exclusively to tree age (insect galleries and exposed sapwood) without responding to diameter. Thus, the retention of trees for conservation purposes based on tree diameter appears to be a generally feasible approach with a rather low risk of underrepresentation of TreMs. Because greater tree age and diameter positively affected TreM development, placing a greater emphasis on conserving large trees and allowing them to reach older ages, for example, through the establishment of conservation reserves, would better maintain the continuity of TreM resource and associated biodiversity. However, this approach may be difficult due to the widespread intensification of forest management and global climate change.

Bark Stripping by Deer Disturbs Regeneration in a Larix–Abies Subalpine Forest

Deer can slow the natural succession of forests from light-demanding to shade-tolerant species or even keep forests in an early successional stage. This study examined the effects of bark stripping by deer (Cervus nippon) on the stand dynamics in a Larix kaempferi–Abies veitchii subalpine forest in central Japan. Bark stripping by C. nippon was concentrated on smaller A. veitchii individuals, and the number of stems with stripped bark increased over the study period (2007–2019). Unlike other tree species in the study plot, the main mortality factor of A. veitchii was bark stripping. In addition, the mortality factors of A. veitchii clearly differed among tree sizes: smaller A. veitchii trees (diameter at breast height ≤ 15 cm) died owing mainly to bark stripping, whereas larger individuals died owing mainly to uprooting, snapping, and standing dead trees. At this forest site, bark-stripping deer preferred the late-successional species (A. veitchii) to the early-successional species (L. kaempferi), and consequently, the progress of succession was disturbed.

Measuring tree stem diameters and straightness with depth-image computer vision

Current techniques of forest inventory rely on manual measurements and are slow and labor intensive. Recent developments in computer vision and depth sensing can produce accurate measurement data at significantly reduced time and labor costs. We developed the ForSense system to measure the diameters of trees at various points along the stem as well as stem straightness. Time use, mean absolute error (MAE), and root mean squared error (RMSE) metrics were used to compare the system against manual methods, and to compare the system against itself (reproducibility). Depth-derived diameter measurements of the stems at the heights of 0.3, 1.4, and 2.7 m achieved RMSE of 1.7, 1.5, and 2.7 cm, respectively. The ForSense system produced straightness measurement data that was highly correlated with straightness ratings by trained foresters. The ForSense system was also consistent, achieving sub-centimeter diameter difference with subsequent measures and less than 4% difference in straightness value between runs. This method of forest inventory, which is based on depth-image computer vision, is time efficient compared to manual methods and less computationally and technologically intensive compared to Structure-from-Motion (SFM) photogrammetry and ground-based LiDAR or terrestrial laser scanning (TLS).

Fire-caused mortality within tree neighborhoods increases growth of Pinus lambertiana more than growth of Abies concolor

Global increases in large-tree mortality and multiple disturbances such as fire, drought, and pestilence increase the importance of understanding how large-tree growth responds to changes in competitive neighborhoods. We used 34,175 spatially mapped trees within 25.6 ha that burned at low to moderate severity in 2013 to investigate how changes to tree neighborhoods affected growth of 3,652 surviving trees of two species, Abies concolor (white fir) and Pinus lambertiana (sugar pine). Using diameter measurements taken in 2014 and 2019, we estimated post-fire radial growth of each surviving tree. We modeled annual basal area increment as a function of diameter and extracted residuals to yield relative growth rate (RGR). We used a multi-model approach and AIC to compare the species-specific effects on RGR of all post-fire tree mortality within a neighborhood radius versus mortality broken down by cause. To represent density reduction around each surviving tree, we computed crowding metrics for neighborhood radii up to 20 m for all tree mortality combined and for each mortality cause. The best-fit model included terms for density reduction within 10 m of the surviving tree due to 1) fire or mechanical damage and 2) bark beetle mortality, as well as their interactions with species and diameter. Density reduction due to fire or mechanical damage had a positive effect on RGR that was nearly twice as strong for P. lambertiana as A. concolor. Tree diameter interacted with density reduction for just P. lambertiana. Small-diameter (10-cm) P. lambertiana had a fourfold larger increase in basal area increment than large-diameter (60-cm) P. lambertiana as density reduction due to fire or mechanical damage ranged from 0 to 100 %. The strong growth response of medium-diameter P. lambertiana to density reductions could eventually increase the abundance of large-diameter (≥60 cm) P. lambertiana. In conjunction with mortality rates, which were lower for large-diameter P. lambertiana (0.97 %) than A. concolor (3.31 %), this could increase the relative abundance of large-diameter P. lambertiana from 51.2 % in 2020 to 62.6 % by 2050. Changes to competitive neighborhoods can have species-specific effects on large-tree growth, an important consideration for long-term management of fire-prone forests.

Vegetation and Forest Complexity Analysis of the Caucasian Grouse (Lyrurus mlokosiewiczi) Habitats in the Lesser Caucasus Mountain

Species composition can vary among different types of habitat and is defined by the dependency of species on resources. The positive relationship between species composition and forest functions is of increasing interest to researchers. In this study, we focused on the species composition and structural complexity index (SCI) of the Caucasian grouse (Lyrurus mlokosiewiczi) habitat, which is an indicator species in mountain forest habitats in the Arasbaran biosphere reserve, Iran. Data were collected from the previously identified presence and pseudo-absence locations of this species. A total of 18 sample plots were surveyed systematically randomly in each area with 800 m distance from each other (36 sample plots in total). The main parameters were type of species, diameter and height of trees, shrubs and regeneration, and number and diameter of coarse woody debris. Overstorey tree species richness per ha differed in the pseudo-absence and presence locations, with 16 and 20 species, respectively. The Caucasian grouse was observed in the site with trees smaller than 10 cm DBH and a balanced density of trees smaller than 5 cm DBH. Overall, the SCI was higher in the presence location than in the pseudo-absence location with no significant difference (t = 1.491, p-value= 0.154). The heterogeneity of the stand structure in grouse habitats was high. The area where the Caucasian grouse was present was characterized by high numbers of dead trees and also high log volume. Maintaining a heterogenous forest structure is important for protecting this species. Conservation of fruit trees that are fed on by the grouse is also recommended.

Overstorey-understorey interactions reveal trade-offs for achieving competing land-use goals in jarrah forest restored after bauxite mining: Initial prescription and targets affect restoration success over 32 years

Quantitative ‘completion criteria’ agreed between mining companies and regulatory authorities are typically used to assess restoration outcomes. Completion criteria provide the basis for determining whether mining companies have fully met their obligations for site restoration. Relationships among potentially conflicting criteria, particularly around site productivity (e.g., timber production), the return of biodiversity, long-term ecosystem trajectories and other ecosystem services remain poorly understood during the development of mine restoration.For the jarrah forest of southwest Australia, we manipulated site productivity in post bauxite mine restoration by establishing four initial Eucalyptus marginata (jarrah) tree stocking rates in factorial combination with seeding a range of large N2-fixing understorey legume species. We measured jarrah growth rates over the 32-year duration of the experiment, soil-N concentrations at 3 and 32 years-of-age and understorey plant species richness and cover at 15 and 32 years-of-age.Stand basal area over bark (BA) increased with increasing tree stocking rates. However, there was a significant negative effect of increasing stand BA on understorey plant cover and species richness. These negative effects were still significant 32 years after the commencement of the experiment.Seeding large understorey legumes increased total soil-N. However, this did not increase tree growth. Rather, seeding large legumes reduced tree survival and diameter at breast height, and reduced understorey species richness, even though the applied seed mix in the large legume treatment contained 14 more species compared with the control.Our data highlight trade-offs between individual aspects of restoration success, such as tree stocking rates and understorey species richness. Further these results suggest reducing site productivity, by the judicious use of large understorey legumes and establishing low tree stocking rates, may facilitate the return of diverse vegetation communities. Finally, it is important to recognise that when restoration success is viewed through the lens of one-dimensional metrics such as completion criteria, restoration may function as a ‘zero-sum game’ in which a gain for one outcome (e.g., N2-fixation) may result in a loss to one or more other outcomes (e.g., tree growth and species richness).

Basal area growth response of Scots pine to drainage: An analysis using a mixed-effects modelling approach

Wood production in peatland forests is often associated with management of site hydrology that aims to improve soil moisture status and stand growth. Silvicultural outcomes of ditching activities vary greatly among drained sites, therefore new data and modelling approaches are necessary for better understanding of forest growth dynamics on a tree-level and a long-term scale. A mixed-effects model estimating growth response to initial ditching performed 40 years ago in Ongassaare region (northeast Estonia) was developed using basal area increment data derived from ring-width series of 287 Scots pine trees from 39 stands. The model indicated that ditching response was up to around 800 mm2 year−1 on average; this level of drainage-induced additional increment was reached 16 years after treatment. Pre-drainage tree diameter, mean stand diameter and radial growth rate were among the significant predictors, therefore the results suggest that tree size, stand growing stock and site quality or microsite conditions before the ditching are affecting post-drainage tree growth. Smaller trees experienced greater growth response; however larger trees responded to the treatment faster than smaller ones. Ditching therefore induced changes in stand structure by decreasing tree size variation. Ditching response was more pronounced in stands with smaller pre-drainage diameter, faster growing trees reached the maximum response values quicker. Trees closer to the drainage ditch responded slightly more intensively to changing site conditions, however, this relationship was significant in the case of a reference ditch (one of the ditches surrounding a forest stand, selected according to the topography of the landscape) but not the nearest one. Drained peatlands are very diverse in terms of pre-treatment site conditions, stand history and ditch network design, therefore additional data from extended network of sample plots would be necessary for updating the developed model to make it more applicable for further use (e.g., predicting forest growth and yield).