Dendrochronological Analyses and Whole-Tree Dissections Reveal Caliciopsis Canker (Caliciopsis pinea) Damage Associated with the Declining Growth and Climatic Stressors of Eastern White Pine (Pinus strobus)

Abstract

Eastern white pine (Pinus strobus) is considered a signature species in eastern North America, particularly in New England. In recent years, however, white pine has experienced increased damage due to native pathogens that reduce the species’ growth, productivity, and economic value. One disease of concern is Caliciopsis canker, caused by the fungal pathogen Caliciopsis pinea, which is associated with excessive resin production, cankers, rough bark, bark fissures/cracks, and reduced growth in white pine. Recent studies have documented the extent of Caliciopsis canker in New England and its association with soil and stocking conditions, yet few studies have focused on the biological impacts of the disease. This study used dendrochronology and whole-tree dissections to reconstruct Caliciopsis canker history in three New England white pine sites, quantify its impact on tree growth and vigor, identify pre-disposing factors, and assess potential silvicultural management options. Dendrochronology and whole-tree dissections provided a unique insight into canker damage throughout trees’ development. Canker damage was first reported in New Hampshire in the mid-1990s, yet cankers were present as far back as 1967 and have steadily increased since the mid-1980s. Increased canker damage was significantly associated with decreased live crown ratios and declining tree growth. Trees maintaining a 30% live crown ratio or greater generally experienced the least canker damage. Furthermore, peaks in canker occurrence were consistent across sites, indicating a regional synchronization of infection and damage. Canker damage was closely associated with climatic events such as droughts and a New England hurricane. The results suggest that Caliciopsis canker has been affecting white pine health over the last 40 years, and that the disease has become more prevalent in the past 20–30 years. Yet, our results suggest that if silvicultural prescriptions target low density thinnings that favor trees with higher live crown ratios (>30%) and low Caliciopsis symptom severity ratings, the risk of canker damage can be reduced in white pine stands.

Fire, insect and disease‐caused tree mortalities increased in forests of greater structural diversity during drought

“…Stressed trees tend be more susceptible to insects and pathogens than healthy ones (Coyle et al, 2015;Roberts et al, 2020); this pattern is well documented for tree mortality caused by both insects (e.g. D. ponderosae and D. frontalis) (Hood et al, 2016;Negrón et al, 2017) and diseases (Bendixsen et al, 2015;Costanza et al, 2020;McIntire et al, 2018). Third, there may also be a greater concentration of insect pheromones in forests with higher SSD where the different sized trees are barriers to wind.…”

“…ponderosae and D . frontalis ) (Hood et al, 2016; Negrón et al, 2017) and diseases (Bendixsen et al, 2015; Costanza et al, 2020; McIntire et al, 2018). Third, there may also be a greater concentration of insect pheromones in forests with higher SSD where the different sized trees are barriers to wind.…”

Silvicultural treatments improve pest and disease conditions of white pine (Pinus strobus) residual trees and regeneration

“…Shelterwoods and low-density thinnings are the most prescribed silvicultural treatments for management of eastern white pine insect pests and diseases (Ostry et al, 2010;Livingston et al, 2019). These treatments can reduce disease incidence and severity at the stand level by improving condition of residual trees and removal of the weakest trees during harvesting operations (McIntire et al, 2018a;Costanza et al, 2020). Harvesting operations to implement these treatments can result in abundant white pine regeneration (Leak and Yamasaki, 2013).…”

“…Since then, other native pests and diseases such as brown spot needle blight, Caliciopsis canker, and eastern white pine bast scale have caused unprecedented damage (Mech et al, 2013;Broders et al, 2015;Munck et al, 2015;Schulz et al, 2018a,b;Wyka et al, 2018;Costanza et al, 2019;Cram and Fraedrich, 2022). Although the impacts of silvicultural treatments on residual trees in stands damaged by these diseases have been evaluated (McIntire et al, 2018a,b;Costanza et al, 2019Costanza et al, , 2020, the impact of these pests and diseases to regeneration following silvicultural treatments is less understood. For example, reducing stand density by thinning improves residual tree growth and symptom severity in stands affected by Caliciopsis canker and foliar diseases (McIntire et al, 2018a;Costanza et al, 2020).…”

“…Although the impacts of silvicultural treatments on residual trees in stands damaged by these diseases have been evaluated (McIntire et al, 2018a,b;Costanza et al, 2019Costanza et al, , 2020, the impact of these pests and diseases to regeneration following silvicultural treatments is less understood. For example, reducing stand density by thinning improves residual tree growth and symptom severity in stands affected by Caliciopsis canker and foliar diseases (McIntire et al, 2018a;Costanza et al, 2020). Partial shading and high seedling density recommended to control WPBR and weevil damage (Ostry et al, 2010) may increase humidity in the understory, creating conditions favorable to the reproduction and dispersal of foliar and canker fungal pathogens.…”