Next Article in Journal
Terrestrial Bryophyte and Lichen Responses to Canopy Opening in Pine-Moss-Lichen Forests
Next Article in Special Issue
Positive Results of an Early Intervention Strategy to Suppress a Spruce Budworm Outbreak after Five Years of Trials
Previous Article in Journal
Transformation of Multi-Antibiotic Resistant Stenotrophomonas maltophilia with GFP Gene to Enable Tracking its Survival on Pine Trees
Previous Article in Special Issue
Effects of Hardwood Content on Balsam Fir Defoliation during the Building Phase of a Spruce Budworm Outbreak
Article

Spatial-Temporal Patterns of Spruce Budworm Defoliation within Plots in Québec

Faculty of Forestry and Environmental Management, University of New Brunswick, P.O. Box 4400, Fredericton, NB E3B 5A3, Canada
*
Author to whom correspondence should be addressed.
Forests 2019, 10(3), 232; https://doi.org/10.3390/f10030232
Received: 24 January 2019 / Revised: 27 February 2019 / Accepted: 1 March 2019 / Published: 6 March 2019
(This article belongs to the Special Issue Protection Strategy against Spruce Budworm)
We investigated the spatial-temporal patterns of spruce budworm (Choristoneura fumiferana (Clem.); SBW) defoliation within 57 plots over 5 years during the current SBW outbreak in Québec. Although spatial-temporal variability of SBW defoliation has been studied at several scales, the spatial dependence between individual defoliated trees within a plot has not been quantified, and effects of defoliation level of neighboring trees have not been addressed. We used spatial autocorrelation analyses to determine patterns of defoliation of trees (clustered, dispersed, or random) for plots and for individual trees. From 28% to 47% of plots had significantly clustered defoliation during the 5 years. Plots with clustered defoliation generally had higher mean defoliation per plot and higher deviation of defoliation. At the individual-tree-level, we determined ‘hot spot trees’ (highly defoliated trees surrounded by other highly defoliated trees) and ‘cold spot trees’ (lightly defoliated trees surrounded by other lightly defoliated trees) within each plot using local Getis-Ord Gi* analysis. Results revealed that 11 to 27 plots had hot spot trees and 27% to 64% of them had mean defoliation <25%, while plots with 75% to 100% defoliation had either cold spot trees or non-significant spots, which suggested that whether defoliation was high or low enough to be a hot or cold spot depended on the defoliation level of the entire plot. We fitted individual-tree balsam fir defoliation regression models as a function of plot and surrounding tree characteristics (using search radii of 3–5 m). The best model contained plot average balsam fir defoliation and subject tree basal area, and these two variables explained 80% of the variance, which was 2% to 5% higher than the variability explained by the neighboring tree defoliation, over the 3–5 m search radii tested. We concluded that plot-level defoliation and basal area were adequate for modeling individual tree defoliation, and although clustering of defoliation was evident, larger plots were needed to determine the optimum neighborhood radius for predicting defoliation on an individual. Spatial autocorrelation analysis can serve as an objective way to quantify such ecological patterns. View Full-Text
Keywords: Choristoneura fumiferana; annual defoliation; spatial autocorrelation; spatial-temporal patterns; mixed effect models; intertree variance Choristoneura fumiferana; annual defoliation; spatial autocorrelation; spatial-temporal patterns; mixed effect models; intertree variance
Show Figures

Figure 1

MDPI and ACS Style

Li, M.; MacLean, D.A.; Hennigar, C.R.; Ogilvie, J. Spatial-Temporal Patterns of Spruce Budworm Defoliation within Plots in Québec. Forests 2019, 10, 232. https://doi.org/10.3390/f10030232

AMA Style

Li M, MacLean DA, Hennigar CR, Ogilvie J. Spatial-Temporal Patterns of Spruce Budworm Defoliation within Plots in Québec. Forests. 2019; 10(3):232. https://doi.org/10.3390/f10030232

Chicago/Turabian Style

Li, Mingke; MacLean, David A.; Hennigar, Chris R.; Ogilvie, Jae. 2019. "Spatial-Temporal Patterns of Spruce Budworm Defoliation within Plots in Québec" Forests 10, no. 3: 232. https://doi.org/10.3390/f10030232

Find Other Styles
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Search more from Scilit
 
Search
Back to TopTop