Dead wood profile of a semi-natural boreal forest - implications for sampling

Abstract

Dead wood profile of a forest is a useful tool for describing forest characteristics and assessing forest disturbance history. Nevertheless, dead wood profiles, including both coarse and fine dead wood, are rare as well as studies on the effect of sampling intensity on the dead wood estimates. In a semi-natural boreal forest, we measured every dead wood item over 2 cm in diameter from 80 study plots. From eight plots, we further recorded dead wood items below 2 cm in diameter. Based on these data we constructed the full dead wood profile, i.e. the overall number of dead wood items and their distribution among different tree species, volumes of different size and decay stage categories. We discovered that while the number of small dead wood items was immense, their number dropped drastically from the diameter below 1 cm to diameters 2-3 cm. Different tree species had notably different abundance-diameter distribution patterns: spruce dead wood comprised mainly of the smallest diameter fractions, whereas aspen dead wood had larger share of large-diameter items. Considering volume, most dead wood was large (>10 cm in diameter), out of which 62% was birch. We also observed that the variation in the dead wood estimates was small for the numerically dominant tree species and smallest diameter categories, but high for the sub-dominant tree species and larger size categories. In conclusion, the more the focus of the dead wood inventory is on rare tree species and large dead wood items, the more comprehensive should the sampling be.

Precision, Applicability, and Economic Implications: A Comparison of Alternative Biodiversity Offset Indexes

“…In natural boreal forests, the amount and type of dead wood are one of the most important structural components (Stokland et al 2004 ): on average 25% of above-ground wood biomass is dead wood in natural forests, and it is a key factor in species diversity (Siitonen 2001 ). Thus, dead wood is often considered as an indicator of forest naturalness and biodiversity in the boreal zone (Halme et al 2019 ; Kunttu et al 2015 ; Similä et al 2006 ). In addition to dead wood volume, the quality of dead wood should be considered (Halme et al 2019 ; Stokland et al 2004 ), which we have done by using decay stages.…”

“…Thus, dead wood is often considered as an indicator of forest naturalness and biodiversity in the boreal zone (Halme et al 2019 ; Kunttu et al 2015 ; Similä et al 2006 ). In addition to dead wood volume, the quality of dead wood should be considered (Halme et al 2019 ; Stokland et al 2004 ), which we have done by using decay stages. However, the dominating role of dead wood in the calculations and the rather limited number of components decrease the generalizability of the results outside the boreal zone concerning the cost-effectiveness of different measures of producing the offset.…”

Availability and Structure of Coarse Woody Debris in Hemiboreal Mature to Old-Growth Aspen Stands and Its Implications for Forest Carbon Pool

“…Our results are also somewhat higher than the mean CWD volume across forests in Latvia for managed and unmanaged stands together: according to NFI, 19.8 m 3 ha −1 . The studied unmanaged stands comprised about 70 to 90 m 3 ha −1 , which is in between average deadwood volume of 40 to 170 m 3 ha −1 in boreal unmanaged forests [11,[50][51][52].…”

“…Our studied aspen stands had a high proportion of deciduous debris (pooled aspen and other deciduous species), accounting for 55% of total CWD in mature stands to 85% in old-growth stands (Figure 3). The higher portion of coniferous deadwood in mature stands likely originated from understory spruce, which typically forms small fractions of debris due to self-thinning [11]. As stand ages, death from the senescence of aspen and other pioneer species (B. pendula, B. pubescens, and A. incana were most common) increases, forming canopy gaps.…”

“…Aspen is commonly regarded as 'keystone species' in the boreal and hemiboreal forests because both living and dead aspen trees host more specialist and endangered species than other tree species in the region [4][5][6][7]. Information of aspen deadwood volume and characteristics, however, is limited, with only some insights from studies in boreal [6,[8][9][10][11] and hemiboreal [12] forests.…”