DOI: 10.5061/dryad.b5mkkwhdh
title: Changes in leaf litter decomposition of primary Korean pine forests after degradation succession into secondary broad-leaved forests

description: Forest degradation succession often leads to changes in forest ecosystem
 functioning. Exactly how the decomposition of leaf litter is affected in a
 disturbed forest remains unknown. Therefore, in our study, we selected a
 primary Korean pine forest (PK) and a secondary broad-leaved
 forest (SF) affected by clear-cutting degradation, both in Northeast
 China. The aim was to explore the response to changes in the leaf litter
 decomposition converting PK to SF. The mixed litters of PK and SF were
 decomposed in situ (one year). The proportion of remaining litter mass,
 main chemistry, and soil biotic and abiotic factors were assessed during
 decomposition and then we made an in-depth analysis of the changes in the
 leaf litter decomposition. According to our results, leaf litter
 decomposition rate was significantly higher in the PK than that in the SF.
 Overall, the remaining percent mass of leaf litter’s main chemical quality
 in SF was higher than in PK, indicating that leaf litter chemical turnover
 in PK was relatively faster. PK had a significantly higher amount of total
 phospholipid fatty acids (PLFAs) than SF during decomposition. Based on
 multivariate regression trees, the forest type influenced the soil habitat
 factors related to leaf litter decomposition more than decomposition time.
 Structural equation modeling revealed that litter N was strongly and
 positively affecting litter decomposition, and the changes in
 actinomycetes PLFA biomass played a more important role among all the
 functional groups. Selected soil abiotic factors were indirectly driving
 litter decomposition through coupling with actinomycetes. This study
 provides evidence for the complex interactions between leaf litter
 substrate and soil physical-chemical properties in affecting litter
 decomposition via soil microorganisms.
description: We collected the leaf
 litter between late September 2016 and late October 2016 in the primary
 Korean pine forest (PK) and secondary broad-leaved forest (SF). At the end
 of the one-month collection period, the stored litter in each forest was
 mixed and the materials were dried at 65 °C to constant weight before
 being placed into litter bags. In early November 2016, geographically and
 micro-topographically similar quadrats were selected to circumvent spatial
 heterogeneity. Three quadrats were established in PK and SF, each with an
 area of 30 × 30 m, being placed every 20 m in the forest. Nylon bags (20.0
 × 15.0 cm with 0.5 mm mesh) were filled with 10 g of the materials mixed
 beforehand. A total of 200 litter bags were randomly placed in the mineral
 soil at a depth of 0–10 cm (at about 45° angle relative to the soil
 surface) in early November 2016 (corresponding to 0 days) in each quadrat.
 Leaf litter bags were collected (taking 40 bags at a time in each quadrat)
 in 30-Apr-2017, 15-Jun-2017, 31-Jul-2017, 16-Sep-2017, and 1-Nov-2017,
 corresponding to 185, 230, 275, 320, and 365 days from the starting
 date. Forty litterbags were harvested and homogeneously mixed to create
 one sample per quadrat at each sample time in PK and SF, respectively (n =
 3).