Estimation of coarse woody debris stocks in forest ecosystems of Slobozhansky national nature park

Abstract

Dead wood is an important component of forest ecosystems. It performs a number of environmental functions. Coarse woody debris includes standing dead trees, fallen dead trees, fragments of fallen trees (trunks), branches (fragments of branches), and rough tree roots. It is a substrate and habitat for living organisms, including a number of species of mosses, lichens, fungi, invertebrates, as well as birds and mammals. Woody detritus plays an important role in the biological cycle of substances and energy, and carbon deposition, is a source of nutrients. Therefore, the study of quantitative and qualitative features of dead wood, in particular on protected areas, is a considerable nowadays problem.

The aim of the work is to estimate identified by forest inventory stocks of dead wood in forest ecosystems of Slobozhansky NNP by categories, as well as to analyze the distribution of its volumes in stands of dominant tree species and forest types.

The estimation of coarse woody debris stocks was performed based on forest inventory data of Slobozhansky National Nature Park conducted by Ukrainian State Project Forestry Production association “Ukrderzhlisproekt”. Data from 493 forest stands of nine tree species were analyzed. The stock of the following fractions of coarse woody debris was studied: standing dead wood, fallen (downed) dead wood. Data analysis was performed using MS Excel 2016 software.

It was found that the total area of forest stands in which standing or downed dead wood was found during forest inventory was 2149.8 ha, or 47.5% of the total forest area of NNP. The total stock of coarse woody debris was 19478 m³, more than 95% of which is concentrated in the stands of Scots pine (Pinus sylvestris L.) (78.8%) and pedunculate oak (Quercus robur L.) (16.6%). Standing dead wood prevailed (62.1%) fallen dead wood (37.9%) in the structure of dead wood volume. The volume of dead wood was in the range of 5–50 m³∙ha^–1, and on average in studied forest ecosystems in which it was found was 9.1 m³∙ha^–1. In Scots pine forest stands coarse woody debris was found on an area of 1703.5 hectares with total stock of 15355 m³, consists of standing dead trees (9952 m³, 64.8%) and fallen dead wood (5403 m³, 35.2%). The volume of dead wood in forest stands was 5–50 m³∙ha^–1, on average – 9.0 m³∙ha^–1. In pedunculate oak stands coarse wood debris was found on an area of 384.7 hectares with a total stock of 3224 m³, consists of standing dead wood (1469 m³, 45.6%) and fallen dead wood (1755 m³, 54.4%). The volume of dead wood in forest stands was 5–20 m³∙ha^–1, on average – 8.4 m³∙ha^–1.

Only 63.3 ha (2.9%) of the studied forests have a volume of coarse woody debris of 20 m³∙ha^–1 and more, and in 955.4 ha (44.4%) of stands it does not exceed 5 m³∙ha^–1. Dead wood was found in forests growing in 11 forest types, but most of it was concentrated in fresh oak-pine subir (9855 m³, 50.5%), less – in fresh linden-oak-pine sugrud (5678 m³, 29.2%) and fresh maple-linden dibrova (2836 m³, 14.6%). The average volume of coarse wood debris by forest types is from 5.0 m³∙ha^–1 (slightly wet black alder sugrud) to 10.5 m³∙ha^–1 (fresh linden-oak-sugrud).About half (50.4%) of coarse woody debris stock is concentrated in medium stocking degree forest stands. More than half (56.8%) of the dead wood stock is in I bonitet class stands. 15,199 m³ (78.0%) of the total found stock of dead wood is concentrated in planted forests, and 4,279 m³ (22.0%) in forests of natural origin.

Obtained results indicate that in general, the dead wood volumes in forest ecosystems of Slobozhansky NNP estimated based on State Forest Inventory data, are quite low compared to the forest ecosystems of other protected areas, where one of the priorities are the natural complexes protection and biodiversity conservation, which may be associated with the intensity of forestry activities in the past on the territory of the national nature park before its creation.