Stem Volume Tables by Height Classes of Willow Trees in the Northern Taiga Region of the European Part of the Russian Federation

In order to improve the accuracy of forest inventory works, tables of stem volume by height classes of willow trees in the northern taiga region of the European part of the Russian Federation were created. Forest inventory standards have not previously been developed for this species in the northern taiga region. The analytical technique proposed by I.I. Gusev in 1971 for spruce forests of the European North was used in compiling the height class volume tables. It was later adopted for the description of other tree species as well. Diameters and heights of trees were measured at 41 sample plots laid out in the Verkhnyaya Toyma and Arkhangelsk forestries of the Arkhangelsk region; 105 model trees were sampled. In most cases, sample plots were laid out in mixed plantations with the predominance of willow. The data obtained on the sample plots served to determine the parameters of the height class scale. The information source for stem volume of willow trees used to be the stem volume tables for aspen trees. A comparative analysis of the tables compiled for willow trees stems with the tables for aspen taken from the Forest Valuation Handbook for the Northeast of the European part of the Russian Federation was carried out. The analysis shows significant discrepancy in the scales for willow and aspen. The use of aspen height class volume tables for willow leads to a systematic overestimation of wood volumes. Tables of stem volumes by height classes of willow trees are used to determine stand stock with the enumeration data by 4-centimeter diameter classes. The developed tables meet the forest practice requirements. The volume tables by height classes are used to calculate timber reserves when laying out sample plots; to determine the damage level in case of stand damage; and for other practical purposes. For citation: Paramonov A.A., Tretyakov S.V., Koptev S.V., Bogdanov A.P., Tsvetkov I.V. Stem Volume Tables by Height Classes of Willow Trees in the Northern Taiga Region of the European Part of the Russian Federation. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 69–78. DOI: 10.37482/0536-1036-2021-6-69-78

Increment analysis in black locust (Robinia pseudoacacia L.) stand – a case study

The study on the diameter and volume increment of black locust (Robinia pseudoacacia L.) stand (age 10-27 years, yield class II) have shown that in comparison to the periodic annual increment of the breast height diameter of tree in height class I, trees in height class II have reached 83.3%, while in class III only 43.9. The same relations for volume were found 59.0% and 24.5%, respectively. The mean values of the whole stand were close to those of height class II. According to the distribution of the periodic annual increment of volume between 10 and 27 years of age, 50% of the values were between 2.00 and13.88 dm3, 73% were between 2.00 and19.82 dm3, and 96% were between 2.00 and 37.64 dm3. The range of 13.88–19.82 dm3 had the highest occurrence (24.5%).

Existing Status of Acacia Woodlands in Central Saudi Arabia: A Case Study in Hawtat Bani Tamim and Al Duwadmi

Acacia woodlands are ecologically important and it is necessary to understand its structures and dynamics to develop sustainable conservation strategies. This study aimed to provide baseline information on the composition and growth of Acacia woodlands in the Hawtat Bani Tamim and Al Duwadmi regions of central Saudi Arabia. Height, diameter at breast height, crown diameter, seedling density, and soil seed bank content of Acacia tree species were characterized for 27 remote, circular, 0.1-ha plots in both study areas. At Hawtat Bani Tamim, Acacia raddiana, A. tortilis, and A. ehrenbergiana accounted for 45.53, 37.5 and 16.96% of all species present there. Most DBH were in the 6–10 cm class. A. raddiana was the main species in most diameter classes. Most trees were 4.1–5.0 m tall and A. raddiana predominated in this height class. Acacia ehrenbergiana had 92.63% damaged seeds. At Al Duwadmi, A. raddiana represented 78.99% of all Acacia trees there. A. gerrardii and A. tortilis accounted for 11.93 and 9.07% of the species there, respectively. Most of the DBH values were in the 6–10 cm and 11–15 cm classes, and A. tortilis and A. raddiana were abundant in both classes. Most trees were in the 4.1–5 m height class, which was dominated by A. raddiana. A. ehrenbergiana had 88.26% damaged seeds. In both areas, there was a gradual decline in the number of trees in DBH classes > 35 cm. The Acacia species in the two areas showed a fair regeneration status. There were more seedlings than saplings and fewer saplings than trees. This baseline study could contribute towards future sustainability planning initiatives after other assessment studies have been conducted to identify changes in the Acacia woodlands of this region. © 2021 Friends Science Publishers

Restoration thinning reduces bush encroachment on freehold farmlands in north-central Namibia

Bush encroachment affects ~45 million ha of Namibia and, without appropriate restoration measures, it negatively affects rangeland productivity and biodiversity. Thinning is a common method to counteract bush encroachment. The thinning strategy applied in north-central Namibia was assessed to examine how effective it has been in reducing bush encroachment. Trees/shrubs were selectively thinned manually, targeting all height classes, except individuals with stem diameters ≥18 cm. We investigated the effects on the vegetation and soil properties using surveys on three freehold farms (in 2016 and 2017) in bush-encroached and previously thinned habitats. Our results revealed significant differences in the mean total nitrogen (TN) content between the treatments; thinned areas had higher TN content which would be beneficial for fast-growing grasses. In the thinned plots, the occurrence probability of red umbrella thorn (Vachellia reficiens Warwa) was significantly reduced, indicating that it was the most harvested species; and umbrella thorn (Vachellia tortilis (Burch.) Brenan spp. heteracantha) was increased, indicating that it favoured reduced densities of dominant species. Natural regeneration was rapid; the tree/shrub abundance in the 0–1-m height class in the thinned area surpassed those in the non-thinned by 34 per cent, ~7.2 years since thinning. Thinning significantly reduced tree/shrub abundances of the 1–3- and >3-m height classes, which was still evident 7.2 years since thinning. Based upon the generalized linear mixed-effects model, tree/shrub counts between treatments may equalize in ~14 and 15 years for the 1–3- and >3-m height classes, respectively. Thinning was effective in reducing tree/shrub abundances and can be used to restore wildlife habitat on the Namibian farmland: however, post-thinning management is required to maintain an open savannah vegetation structure as the 0–1-m height class cohort will eventually grow into mature trees/shrubs.

Effects of Ontogenetic Development on Seedling Regeneration Dynamics of Quercus Acutissima Plantation in Mount Tai

Background: Natural regeneration is critically important for the sustainable management of artificial forests. Studies have been investigated for the effects of seedlings height distribution and ontogenetic adaptability in a 60-year-old Quercus acutissima artificial pure forest in Mount Tai. Results: The results showed that the height distribution of seedlings under the forest was pyramidal-shape from the year 2010 to 2017. In 2017, the density of seedlings under the forest was only 61.63% of that in 2010, and the number of individuals at each height class was lower than that in 2010, especially the individuals at 20-40cm height class only 32% of that in 2010. With the increase of seedling height under the forest, seedling biomass (SB), ground diameter (GD), root mass ratio (RMR), total root length (TRL), root volume (RV), root average diameter (RAD) and nonstructural carbohydrates (NSC) increased significantly, but leaf mass ratio (LMR), leaf area ratio (LAR), photosynthetic/non-photosynthetic tissue ratio (P/NP), specific root length (SRL) and specific root surface area (SRA) decreased significantly. Correlation analysis showed that SB was negatively correlated with LMR, LAR, P/NP, SRL and SRA, and positively correlated with RMR, TRL, RV, RAD and NSC. NSC was negatively correlated with LMR, LAR, P/NP, SRL and SRA. Conclusions: Therefore, with the increase of seedlings height, the increased carbon storage was helpful for the seedlings of Q. acutissima to survive under the forest for a long time, but the reduced ability of light interception, photosynthetic tissue ratio, water and nutrient absorption capacity contributed to their low survival ratio under the forest.

Caractéristiques de la flore et de la végétation ligneuses des parcs agroforestiers de l’arrondissement de Tendouck (Basse Casamance, Sénégal)

L’agriculture occupe une place très importante dans l’arrondissement de Tendouck. Pour augmenter leurs rendements, les agriculteurs laissent délibérément dans leurs champs certaines espèces ligneuses. Cette étude a pour objectif général de contribuer à une meilleure connaissance des caractéristiques des parcs agroforestiers du département de Bignona. Pour ce faire, une placette de 2500 m² (50 mx50 m) a été installée dans les champs de chaque agriculteur retenu dans un échantillon de 98 agriculteurs. Cet échantillon est réparti entre les différentes communes de l’arrondissement au prorata de leur poids démographique soit 16 ; 21 ; 22 ; 30 et 9 placettes respectivement dans les communes de Balinghore, Diégoune, Kartiack, Mangagoulack et Mlomp. La flore dans l’arrondissement de Tendouck est riche de 53 espèces réparties en 45 genres relevant de 20 familles botaniques. Au niveau de l'arrondissement de Tendouck la densité des arbres des parcs agroforestiers est de 42 pieds/ha, la surface terrière de 3,21 m²/ha et le taux de recouvrement de 18,82%. Ces parcs sont très diversifiés avec un indice de Shannon de 3,91 et un indice de Pielou de 0,79. Le taux de régénération y est très important (88,19%). La structure par classes de hauteur du peuplement ligneux des parcs agroforestiers révèle une prédominance des jeunes individus avec 24,73% des individus appartenant à la classe de hauteur [2-4 m]. La classe de diamètre la plus représentée est [5-20 cm] avec 42, 99% des individus. Ces résultats constituent une base pour une gestion rationnelle et durable de ces écosystèmes en vue de permettre aux agriculteurs de mieux tirer profit de leurs services dans l’arrondissement de Tendouck. Il apparait ainsi judicieux de poursuivre cette étude dans les autres départements de la Basse Casamance en vue de disposer d’une base de données des parcs agroforestiers de cette zone éco géographique.Mots clés: Champs, composition floristique, structure, agriculteurs, caractéristiques structurales English title: Characteristics of the woody flora and vegetation in the agroforestry parks of the Tendouck district (Lower Casamance, Senegal)Agriculture occupies a very important place in the district of Tendouck. In order to increase their yields, farmers deliberately leave certain woody species in their fields. The general objective of this study is to contribute to a better knowledge of the characteristics of agroforestry parks in the Bignona district. To this end, a 2500 m² (50 mx50 m) plot was installed in the fields of each farmer selected from a sample of 98 farmers. This sample is distributed among the different communes of the district in proportion to their demographic weight, therefore 16; 21; 22; 30 and 9 plots respectively in the communes of Balinghore, Diégoune, Kartiack, Mangagoulack and Mlomp. The flora in the district of Tendouck is rich of 53 species divided into 45 genera belonging to 20 botanical families. At the level of Tendouck district, the density of trees in agroforestry parks is 41.55 trees/ha, the basal area of 3.21 m²/ha and the rate of covering of 18.82%. These parks are very diversified with a Shannon index of 3.91 and a Pielou index of 0.79. The regeneration rate is very high (88.19%). The height class structure of the woody stand in the agroforestry parks reveals a predominance of young individuals with 24.73% of the individuals belonging to the height class [2-4 m]. The most represented diameter class is [5-20 cm] with 42.99% of the individuals. These results provide a basis for rational and sustainable management of these ecosystems with a view to improving the living conditions of farmers in the Tendouck district. It therefore seems advisable to continue this study in the other departments of Lower Casamance in order to have a data of the agroforestry parks of this eco-geographical area.Keywords: Fields, floristic composition, structure, farmers, structural features

Structure and Successional Classification of the Shrub-Arboreal Component in a Remnant of Atlantic Forest, Northeastern Brazil

Aims: We aimed to evaluate the structure and successional classification of component shrub-arboreal in the edge and interior environments in a remnant of Tropical Forest in Pernambuco, Brazil. Place and Duration of Study: The study was conducted in a remnant of the Lowland Ombrophilous Dense Forest categorized as Urban Forest Reserve named Mata of Manassu, with an area approximately 264.24 ha and located in Jaboatao dos Guararapes, Pernambuco. The data were registered between March 2017 and September 2017. Methodology: The data were collected in 40 100 m2 plots, 20 plots in each environment: edge and forest interior. The ‘‘edge’’ was considered to comprise a 100-m strip at the border of the forest and the ‘‘interior’’ at least 300 m in from this strip. In all plots, were cataloged, identified and measured the circumferences at height of the base at 30 cm from the soil of all shrub-arboreal individuals whose height were equal or greater than 1.0 meter and circumference at breast height at 1.30 m of soil, less than 15.0 cm. For the communities on the edge and forest interior were estimated: total density (TD), absolute density (AD), relative density (RD), total frequency (TF), absolute frequency (AF), relative frequency (RF), total dominance (TDo), absolute dominance (ADo), relative dominance (RDo), relative natural regeneration by height class (RNRij), total natural regeneration by height class (TNR), importance value index (IVI) and was performed the distribution analysis of individuals in three height classes using the Chi-square test with 95% significance. The sampled individuals were classified into family, genus, and species, and the species classified for the successional group (pioneers, initial secondary, late secondary or uncharacterized). Results: The environment of the edge showed the highest absolute density (10.240 ind.haˉ¹) to the forest interior (9.805 ind.haˉ¹). In both environments, it was found the high representativity of initial and late secondary species. The structural distributions of individuals by height class at the edge and interior environments showed curves shaped as inverted "J" indicating "dynamic balance" of the forest. Conclusion: The higher representativity of initial and late secondary species probably is due to the forest being in an advanced successional stage, having a structure with well-defined stratum. Among the shrub-arboreal species sampled which presented higher total natural regeneration per height class to both in the edge and forest interior and that can be used for the enrichment of areas in the recovery process of Atlantic Forest are Miconia prasina e Eschweilera ovata.

Development of standards of assessment of volume of logging residues produced in the process of illegal logging

В ходе проведенного исследования доказаны возможность и целесообразность составления лесотаксационных нормативов по оценке объемов порубочных остатков, оставляемых после самовольных рубок, на основе математических моделей надземной фитомассы деревьев. Технологичность и высокая точность таких нормативов могут быть обеспечены на основе стыковки данных по фитомассе деревьев с применяемыми на производстве таблицами объемов стволов. В этом процессе наилучшие результаты обеспечиваются при использовании в стыковочных уравнениях фитомассы объема ствола в качестве одной из независимых переменных. В целях более полного учета в разрабатываемых нормативах природных закономерностей формирования крон и их структурных частей в этих уравнениях целесообразно наряду с объемом использовать возраст и показатель D : H деревьев. На основе полученных трехфакторных уравнений установлено, что масса кроны и хвои у деревьев одинаковой толщины закономерно возрастает от высших разрядов высот к низшим, а в пределах одного разряда высот − с уменьшением возраста древостоев. Эти изменения соответствуют природным закономерностям накопления фитомассы крон в древостоях. Информативность и востребованность нормативов значительно возрастают, если в них наряду с весовыми показателями будут представлены и объемные. Процедура перехода в объемные показатели в плотной мере корректно решается с использованием соответствующих коэффициентов плотности фракций фитомассы, а в объемные показатели в складочной мере – коэффициентов их полнодревесности. Для определения объема порубочных остатков при помощи разработанных нормативов в лесных выделах, пройденных самовольными рубками, производится измерение диаметров пней по 4-сантиметровым ступеням толщины и определение по ним диаметров стволов на высоте груди по соответствующим таблицам. The article proves the possibility and expediency of compiling forest taxation standards based on mathematical models of the aboveground phytomass of trees for estimating the volumes of logging residues left after illegal logging. Data docking of the phytomass of the trees and the volume tables ensure the manufacturability and high accuracy of such standards. It is noted that the using the volume stem in docking equations of phytomass gives the best results. It should be stressed that to take into account the natural laws of the formation of crowns and their structural parts, it is advisable to use the volume, age and ratio D : H of trees in the equations. On the basis of the obtained equations, it is established that the weight of the crown and needles in trees of the same thickness increases regularly from the top height classes to the bottom ones, and within one height class increases with a decrease in the age of the tree stands. It is reported that informativeness and demand for standards increases if weight and volume parameters are used together. The procedure for the transition to volume parameters in a solid measure is solved with the use of the corresponding density coefficients of the phytomass fractions, to the volume parameters in the stacked measure with the use of their stacking factors. Recommendations are given on the basis of the developed standards for determining the volume of logging residues in forest strata, left after illegal logging.

Morphological variation of Cedrela odorata (Meliaceae): contrast between natural and managed populations

Background and Aims: Cedrela odorata (Spanish cedar) is a tropical tree native to America with an important international trade market. In this study, the morphological variation of C. odorata was compared among three conditions: logging, plantations, and natural populations, with the objective to evaluate the current condition of managed populations after harvesting and in plantations, in contrast to relatively well-preserved populations.Methods: Two sites were chosen for each condition. The population density and four morphological attributes were measured: diameter at breast height, height, angle of branch insertion and crown form. A multivariate approach was used to compare the morphological variation among conditions (generalized discriminant factors analysis) and determine total variation distributed among size classes (cluster analysis), as well as assignment of these classes to each condition (canonical correspondence analysis).Key results: Four significantly different size classes were identified among all populations with specific association to condition. Strongest correlations were between highest trees with natural populations and small trees with plantations. Forest management, including harvesting and plantation conditions, reduced the phenotypical variation and modified the dasometrical attributes of C. odorata. The logging of the better shaped phenotypes increased the smaller size trees frequency compared to commercial size individuals, and changed the forest composition favoring small categories.Conclusions: The forest exploitation generates homogenization in median height-class and the plantation in lower height-class. In both cases, the harvestable trees are scarce, even after 20 years of management; and they are non-existent in plantations of 15 years. These results suggest that the removal of the highest trees, as well as forest plantations, are not being effective to wood production since they do not reach commercial sizes in the time of recovery or projected growth.