Summary
Published in For. Ecol. Manage. 495: 119375. https://doi.org/10.1016/j.foreco.2021.119375
Understory vegetation plays an important role in maintaining biodiversity, soil nutrient cycling and carbon stocks, yet the ability of understory functional traits to predict forest productivity after harvesting disturbance is unknown. Our objective was to investigate the utility of individual traits (the community-weighted trait mean) and combined information from multiple traits (functional diversity indices) of understory plants in predicting tree diameter growth of black spruce (Picea mariana (Mill.) B.S.P.) after two harvesting methods (clearcutting and careful logging). We used vegetation and tree growth data from a network of field plots (171 plots on 43 sites) established in black spruce dominated forests across Ontario and Quebec, in northeastern Canada. Functional traits (11 traits) of dominant understory species that reflect plant morphology, regeneration strategy, and resource utilization were collected. We then used generalized linear mixed models (GLMMs) to model the response of tree diameter increment to functional diversity indices, community-weighted trait means and their interactions with harvesting method. Our results showed that: 1) at the functional diversity level, functional richness had a positive relationship with tree growth in clear-cut forests, while functional evenness showed a negative and functional divergence a positive relationship with tree growth in careful logging forests; 2) at the individual trait level, understory species with relatively large morphological trait values often promoted tree growth in both forest types, with stronger relationships in careful logging than in clear-cut forests. For regeneration traits, heavier seed weight or permanent seed bank persistence of understory plants had negative relationships with tree growth, and those relationships were either only found in careful logging forests or did not depend on harvesting type. A positive relationship was found between vegetative propagation species and tree growth, which was stronger in careful logging than in clear-cut forests. Species preferring either humid or xeric habitat had positive relationships with tree growth; both shade-tolerant and shade-intolerant species also positively correlated to tree growth. In conclusion, our study shows the important roles of understory traits in predicting tree growth based on both niche complementarity and mass-ratio hypotheses. Moreover, disturbance severity influenced the balance or degree of the positive and negative interactions that occurred between understory plants and black spruce tree growth. We suggest that identifying the threshold of harvesting disturbance severity that can activate facilitation interactions between understory plants and crop trees would be an important topic for future study.
Sector(s):
Forests
Categorie(s):
Scientific Article
Theme(s):
Forest Ecology, Forestry Research, Forests, Silviculture
Departmental author(s):
Author(s)
WEI, Liping, Nelson THIFFAULT, Martin BARRETTE, Nicole J. FENTON et Yves BERGERON
Year of publication :
2021
Format :
PDF available upon request
How to get the publication :
ISSN
0378-1127
Keywords :
l'effet des traits, complémentarité des niches, hypothèse masse-ratio, coupe totale, coupe avec protection de la régénération et des sols, croissance des arbres, article scientifique de la recherche forestière, écologie forestière, sylviculture et rendement des forêts naturelles - peuplements résineux, silviculture and yield of natural forests - softwood stands, forest ecology, forestry research scientific article, effect traits, niche complementarity, mass-ratio hypothesis, clearcutting, careful logging, tree growth
