Distribution of mixed coniferous stands in the Luzhsko-Volkhovsky landscape district

Смешанные древостои с преобладанием сосны и ели занимают территории с оптимальными лесорастительными условиями, в отличие от монодоминантных насаждений. Условно чистые древостои в большинстве случаев приурочены к экстремальным условиям местообитания или обусловлены созданием лесных культур. Среди смешанных древостоев с преобладанием хвойных пород однозначно только хвойно-лиственные, а именно – елово-лиственные древостои, связываются с антропогенным воздействием на географический ландшафт. В каждом отдельно взятом ландшафте будет формироваться отличное распределение типов хвойных насаждений по лесопокрытой площади в зависимости от почвенно-гидрологических условий. Оценка пространственного распределения смешанных хвойных древостоев в различных типах леса позволяет дать точную экологическую характеристику и оценку ландшафта и оценить его антропогенную изменённость. Рассматриваются особенности распространения смешанных древостоев с преобладанием сосны и ели в наиболее представленных типах леса в основных ландшафтах Лужско-Волховского ландшафтного округа Ленинградской области. Проведён анализ ландшафтов по распределению покрытой лесом площади по почвенно-гидрологическим условиям и основным обобщённым группам типов леса. Присутствие сложного комплекса холмисто-моренных, камовых, озовых урочищ, чередующихся с заболоченными котловинами и озёрами практически во всех рассмотренных ландшафтах, позволяет сделать заключение, что приуроченность смешанных хвойных древостоев связана с фактором переходных форм рельефа от одной ландшафтной группы к другой. Типологическая приуроченность хвойных полидоминантных древостоев является закономерной для зеленомошной серии типов леса данного ландшафтного округа. Mixed woodlands with a predominance of pine and spruce occupy territory with optimal forest-growing conditions, unlike monodominant plantations. Conditionally clean woodlands are in most cases shortened to extreme habitat conditions or due to the creation of forest crops. Among mixed woodlands with a predominance of conifers, unambiguously only coniferous-deciduous, namely spruce-deciduous woodlands, are associated with anthropogenic effects on the geographical landscape. In each individual landscape, an excellent distribution of the types of coniferous plantations along the covered area will be formed, depending on soil and hydrological conditions. The assessment of the spatial distribution of mixed coniferous trees in different types of forest allows to give an accurate ecological characteristic and assessment of the landscape and to assess its anthropogenic variation. The article considers the distribution features of mixed woodlands with a predominance of pine and spruce in the most represented types of forest in the main landscapes of the Luga-Volkhov landscape district of the Leningrad region. An analysis of landscapes was carried out on the distribution of forest-covered area according to soil-hydrological conditions and the main generalized groups of forest types. The presence of a complex of hilly-moraine, stone, oze tracts alternating with swampy basins and lakes in almost all the landscapes considered allows us to conclude that the confluence of mixed coniferous woodlands is associated with the factor of the transition forms of relief from one landscape group to another. The typological confluence of coniferous polydominant woodlands is natural for a green-haired series of forest types of this landscape district.

Assessing the growth of Picea omorika [Pan.] Purkyn in the Masaryk Forest Training Forest Enterprise at Ktiny

Plantations of Serbian spruce (Picea omorika [Panč.] Purkyně) reach an age over 70 years at the Masaryk Forest Training Forest Enterprise (TFE) at Křtiny. They occur at different sites of the TFE, which is situated north of Brno between Blansko, Jedovnice and Brno in the Czech Republic. The paper presents an assessment of primary mensurational values (diameter at breast height d.b.h., height h, Derbholz volume m³), fertility, mortality and general health condition. The present registered number of Serbian spruce trees is 425 (from originally 750 individuals) in 25 localities and 12 GFT (groups of forest types). A comparison of Serbian spruce mensurational data with growth tables indicated that Serbian spruce on GFT 4K makes up for the tabular mean values of Norway spruce (Picea abies [L.] Karst.) in yield class +1.

Terrain properties of selected forest sites in the Jizerské hory Mts., Czech Republic

Differentiation of forest technologies according to ecosystem properties is a necessary step to achieve sustainable forestry. A forest typological system is considered to be the basic unit of ecosystem differentiation in the Czech Republic. Terrain characteristics, potential water erosion and applicable harvest technology were examined for 44 forest sites in a landscape segment of the Jizerské hory Mts. Forest site was found homogeneous in terms of terrain and technological properties. Edaphic category and groups of forest types as higher classification units and management sets as units of alternative classification showed lower homogeneity insufficient for operational planning.

Automatic classification of surface topography to the quantitative and qualitative characteristics of forests

Целью статьи является поиск взаимосвязей между количественными и качественными характеристиками лесов и морфометрическими характеристиками рельефа. На примере Лисинской части Учебно-опытного лесничества Ленинградской области оценивались регрессионные взаимосвязи между характеристиками лесов и результатами автоматической классификации рельефа. Актуальность данного направления связана с поиском объективных количественных характеристик ландшафтов, способных определять изменчивость характеристик структуры и продуктивности лесов. Сформирован геоинформационный проект модельной территории, разбитый регулярной сеткой с шагом 1000 м на 205 ячеек. Для ячеек регулярной сети определены обобщенные характеристики лесов на основе материалов таксации. В качестве анализируемых характеристик лесов рассматривались доли площади земель, покрытых лесной растительностью; доли площади, занимаемые насаждениями преобладающих древесных пород и группами типов леса, средние запасы на га, средние классы бонитета. На основе цифровой модели рельефа SRTM выполнены четыре варианта автоматической классификации поверхности рельефа методом Ивахаши и Пайка и методом, основанным на анализе индекса превышения (TPI). Взаимосвязи количественных и качественных характеристик лесов с характеристиками поверхности рельефа (классами рельефа) оценивались средствами многофакторного регрессионного анализа. Для каждого варианта автоматической классификации рельефа определен набор из 3–4 некоррелированных между собой классов форм рельефа, способных объяснять изменчивость большинства анализируемых количественных и качественных характеристик лесов. Многофакторные уравнения для разных вариантов классификации демонстрируют аналогичные по силе статистические связи для одних и тех же характеристик лесов (средних запасов и бонитетов, долей площади преобладающих пород и групп типов леса). Дальнейшее развитие результатов исследования может способствовать совершенствованию теории и практики лесоучетных работ на основе количественного анализа пространственных данных о лесных ландшафтах с применением геоинформационных технологий и дистанционных методов. The aim of the article is a search the relationships between the quantitative and qualitative characteristics of forests and morphometric characteristics of the relief. On example of the Lisino part of Uchebno-Opytnoe forest district in Leningrad region were estimated regression relationships between the characteristics of the forest stands and the results of automatic classifications of relief. The urgency of this direction is associated with the search for objective quantitative characteristics of landscapes, that can determine the variability of the characteristics of the structure and productivity of forests. The geoinformation project of model territory was formed and was divided to 205 cells on base of regular grid with step 1000 m. For cells of regular grid were determined generalized characteristics of forests on base of forest mensuration data. As analyzed characteristics of forests were considered the proportion of land area covered by forest vegetation, the proportion of the area occupied by predominant tree species and groups of forest types, average stocks per hectare, the average productivity classes. On base of digital terrain model SRTM were executed four variants for the automatic classification of surface topography by Iwahashi and Pike method, and a method based on the analysis of topographic position index (TPI). The relationships between quantitative and qualitative characteristics of forests with the characteristics of the surface topography (classes of relief) were evaluated by means of multivariate regression analysis. For each variant the automatic classification of the relief was determined a set of 3–4 classes uncorrelated with each other landforms that could explain the variability of the majority of analyzed quantitative and qualitative characteristics of forests. Multivariate equations for the different variants of the classification demonstrates similar statistics in strength due to the same characteristics of forests (average stocks and classes of productivity, shares of area predominate tree species and groups of forest types). The future development of research results can help to improving the theory and practice of forest accounting works based on the quantitative analysis of spatial data on forest landscapes using GIS and remote sensing methods.

THE IMPACT OF SHARE PARTICIPATION OF PINE AND SPRUCE ON INVENTORY INDICES OF MIXED FOREST STANDS

The influence of composition on the dynamics of inventory indices of the mixed modal forest stands is considered: ridges with the groups of forest types of middle subzone of taiga in the territory of the Leningrad region, for 60 year period. The course of growth of pine and spruce in the mixed stand is due to the composition of the stand, which affects the entire life cycle of its development. Analysis of forest inventory data at the test plots has shown that the median line for the average height and diameter has the distinction of growth from tabular reference data. Differences in the dynamics of growth in valuation metrics over the study period is due to the initial density of pine, then spruce, and the degree of difference in the age of trees. The variability of average heights and diameters on the experimental plots is influenced by the share of particular species in the composition of the stand. The stand composition significantly affects average diameter and height of tiers, composing the mixed coniferous forest that was confirmed by single-factor analysis of variance. The sum of the areas of the cross sections at the pine tier of the virtually at all experienced objects increases up to the age of 100-120 years, and in spruce this dependence is shown only up to the age of 80-85 years. Pine tier depending on the initial density has a greater impact on the composition of the mixed stands than spruce. This can be considered as a fact of environmental compliance of the conditions of the types: ridges with groups of forest types, for successful growth of pine. In mixed stands, untouched by commercial logging, the spruce element, quantitatively not exceeding the pine one, are stunted and produce less stock