Canadian Forest Service Publications
Understanding tree growth responses after partial cuttings: A new approach. 2017. Montoro Girona, M.; Rossi, S.; Lussier, J.-M.; Walsh, D.; Morin, H. PLoS ONE 12: e0172653.
Issued by: Laurentian Forestry Centre
Catalog ID: 37871
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Forest ecosystem management heads towards the use of partial cuttings. However, the wide variation in growth response of residual trees remains unexplained, preventing a suitable prediction of forest productivity. The aim of the study was to assess individual growth and identify the driving factors involved in the responses of residual trees. Six study blocks in even-aged black spruce [Picea mariana (Mill.) B.S.P.] stands of the eastern Canadian boreal forest were submitted to experimental shelterwood and seed-tree treatments. Individual-tree models were applied to 1039 trees to analyze their patterns of radial growth during the 10 years after partial cutting by using the nonlinear Schnute function on tree-ring series. The trees exhibited different growth patterns. A sigmoid growth was detected in 32% of trees, mainly in control plots of older stands. Forty-seven percent of trees located in the interior of residual strips showed an S-shape, which was influenced by stand mortality, harvested intensity and dominant height. Individuals showing an exponential pattern produced the greatest radial growth after cutting and were edge trees of younger stands with higher dominant height. A steady growth decline was observed in 4% of trees, represented by the individuals suppressed and insensitive to the treatment. The analyses demonstrated that individual nonlinear models are able to assess the variability in growth within the stand and the factors involved in the occurrence of the different growth patterns, thus improving understanding of the tree responses to partial cutting. This new approach can sustain forest management strategies by defining the best conditions to optimize the growth yield of residual trees.
Plain Language Summary
The results of this study demonstrate that the development of a new model-based approach helps to characterize growth trends for each tree over time and, thus, to quantify growth variability between trees within the same stand. Such models are also helpful in understanding factors that affect the various growth patterns, particularly by identifying the factors at work in how trees respond to partial cuts.
This new approach will help managers better understand the tree growth response following partial cuts and inform their management practice decisions in order to maximize tree growth.