DOI: 10.5061/dryad.4mw6m90bb
title: Coarse woody debris density and carbon concentration by decay classes in mixed montane wet tropical forests (Dataset)

description: This dataset contains data from a study considering the relationship
 between decay class, wood density and C content of CWD in old-growth mixed
 monsoon montane tropical forests in Vietnam based on the inventory of 359
 CWD pieces. The CWD inventories were conducted on forty one (3-4 per site)
 50 m long and 4 m wide transects. The first dataset for contains site
 description, plot and transect numbers with geographical coordinates. All
 CWD pieces of more than 6 cm in diameter were inventoried. The dataset
 contains position of CWD: stumps, standing dead trees (snags), lying logs,
 leaning logs and branches, diameter, proportion consumed by termites,
 decay class, bulk density and moisture of wood and mass loss. The second
 dataset contains the data on the wood density of tree species present in
 the study area according to the global database compiled by Zanne et al.
 (2009).
description: The study was carried out in 2018-2019 in November-December in
 Central Highlands in the Bi Doup - Nui Ba (Vườn quốc gia Bi Doup - Núi Bà)
 national park (N12° 10.885' - 11.235'; E108° 40.469' -
 41.406'). CWD inventories were conducted on forty
 one (3-4 per site) 50 m long and 4 m wide transects. All CWD pieces of
 more than 6 cm in diameter were inventoried. They were distributed by
 position as follows: stumps and standing dead trees (snags) (N=21), lying
 logs (N = 109), leaning logs (N = 72) and branches (N = 42). In total, 359
 CWD pieces of different position were sampled. We
 assigned each sampled CWD individual to a decay class using five decay
 classes that span a spectrum from fresh mortality to nearly complete decay
 with collapsed bole shape. Density sampling
 for CWD wood was performed using a hand saw and a knife at 1-3 locations
 per CWD piece, including the sides of logs. The type of rot (white vs.
 brown) was identified, when possible, based on visual characteristics,
 mainly color and structure (cubes vs. fibers), of residual material. An
 adjustment for volume losses during decomposition was made; the initial
 shape of highly decomposed samples was reconstructed. Small samples of
 regular shape up to 100 cm<sup>3</sup> in size were taken.
 Their length, width and thickness were measured in the field. In 2019, 248
 samples were weighed in order to determine relative wood moisture by decay
 classes. The samples were collected during the dry season, i.e. in
 relatively dry conditions. In
 the laboratory, the samples were oven-dried at 103°C for 48 h and weighed.
 The bulk density of a wood sample (ρ, g cm<sup>-3</sup>) was
 calculated by dividing the dry mass by the fresh volume of a sample. The
 total bulk density of a CWD item was calculated taking into account the
 proportion of wood consumed by invertebrates (void). The mass loss was
 calculated based on the loss of total density, i.e. it included all
 decomposition processes: respiration, consumption by invertebrates,
 fragmentation, leaching etc. 
 The initial bulk density of wood was estimated for
 the tree species (genera) dominating in the studied forest stands based on
 the global wood density database (Zanne et al. 2009) for tropical
 South-East Asia. The tree community-level mean density was calculated as a
 weighted mean. Chemical
 analysis of 259 wood samples was conducted in the Analytical Laboratory of
 Forest Research Institute KarRC RAS. In the laboratory, the samples were
 liophilically dried at -30 -40°С. Mechanical trituration of the samples by
 laboratory mill using liquid nitrogen was used to fix tissues. The C mass
 concentrations were measured for freeze-dried material (1.5-2.5 mg) using
 a Perkin Elmer 2400 Series II CHNS/O Analyzer (USA), calibrated with the
 organic analytical standard acetanilide (Perkin-Elmer №0204-1121).