Hard pine stem rusts on lodgepole pine at a site-preparation study in sub-boreal British Columbia: effects over 24 years

Abstract

Site preparation can improve lodgepole pine (Pinus contorta var. latifolia Engelm. ex S. Watson) survival and growth; however, we lack information regarding possible interactions between treatment effects and the impacts of western gall rust (Endocronartium harknessii (J.P. Moore) Y. Hirats.) and comandra blister rust (Cronartium comandrae Peck). Mechanical and burning techniques examined over 24 years at a sub-boreal British Columbia site did not significantly increase rust infection rates or characteristics relative to an untreated control. Most infection occurred before age 10 years and at heights <2 m. By age 24 years, 22% and 10% of pine had sustained at least one western gall rust or comandra blister rust stem infection, respectively, but only 4% of western gall rust infected trees were dead, compared with 60% of comandra blister rust infected trees. Exploratory regression analysis of the relationship between tree volume and percent stem encirclement and infection height suggested that volume of 24-year-old pine infected with western gall rust averaged 8% less than the corresponding volume of uninfected trees. Over 24 years, estimated stand-level, rust-related volume loss was 8.4%, with the majority due to mortality from comandra blister rust. One-fifth of estimated volume loss was provisionally attributed to growth reductions among live western gall rust infected pine.Résumé : La préparation de terrain peut améliorer la survie et la croissance du pin tordu latifolié (Pinus contorta var. latifolia Engelm. ex S. Watson) mais nous manquons d'information concernant les interactions potentielles entre les effets des traitements et les impacts de la rouille-tumeur autonome (Endocronartium harknessii (J.P. Moore) Y. Hirats.) et de la rouille-tumeur oblongue (Cronartium comandrae Peck). Les méthodes mécaniques et les techniques de brûlage étudiées depuis 24 ans dans une station subboréale de la Colombie-Britannique n'ont pas significativement augmenté les taux d'infection de la rouille ni les caractéristiques relatives au témoin non traité. La plupart des infections sont survenues avant l'âge de 10 ans à des hauteurs <2 m. À l'âge de 24 ans, respectivement 22 % et 10 % des pins avaient été infectés au moins une fois sur le tronc par la rouille-tumeur autonome ou la rouille-tumeur oblongue mais seulement 4 % des arbres infectés par la rouille-tumeur autonome étaient morts comparativement à 60 % des arbres infectés par la rouille-tumeur oblongue. Une analyse de régression exploratoire de la relation entre le volume des arbres, le pourcentage d'encerclement et la hauteur de l'infection a indiqué que le volume des pins âgés de 24 ans et infectés par la rouille-tumeur autonome était en moyenne 8 % plus faible que le volume correspondant des arbres sains. Sur une période de 24 ans, la perte de volume due à la rouille à l'échelle du peuplement a atteint 8,4 %, principalement à cause de la mortalité causée par la rouille-tumeur oblongue. Un cinquième de la perte de volume estimée a été provisoirement attribué aux réductio...

Site preparation severity influences lodgepole pine plant community composition, diversity, and succession over 25 years

“…At Bednesti, false toadflax was found only in older, less-disturbed pine stands, providing tentative support for the view that soil disturbance could reduce this host in the early years when pines are most liable to infection. Contrary to these findings and an earlier analysis by Reich et al (2015),…”

Warning Signals of Adverse Interactions between Climate Change and Native Stressors in British Columbia Forests

“…Extensive damage to individual pine trees in older operational plantations or in replicated experiments has also been observed in other BC studies [14,19,40,46] and has been forecast to intensify under climate change [17]. We found that rates of loss for pine due to killing agents alone either matched the expected rate of loss (TIPSY projections [34]), or were as much as twice as high as expected in the largest diameter trees.…”

“…Warmer and wetter conditions in spring and summer months favor hard pine rusts [38][39][40], the dominant forest pathogens we observed, which combined affected 15% of all lodgepole pine trees. In the only prior extensive survey of forest disturbances in managed stands in BC, a study conducted in the early 1990s, 6% of pine trees were found to be affected by hard pine rusts across the SBS zone [41].…”

Applications of a conceptual framework to assess climate controls of forest tree diseases

“…Summary : A trend towards a greater frequency of years with more spring and summer precipitation and higher overnight minimum temperatures in late summer throughout interior BC has reduced the period between rust wave years (Woods, 2011) to as little as three years on some sites (Reich et al, 2015). This represents an apparent change in disease behaviour from that observed earlier in BC and farther south in the Rocky Mountain states where outbreaks of comandra blister rust had been considered rare (Krebill, 1968).…”

“…Wave years for other stem rusts, including white pine blister rust ( Cronartium ribicola ), comandra and stalactiform blister rust, require moderate temperatures and moist conditions in mid‐ to late summer (Hunt, 2004; Krebill, 1968; Van Arsdel et al, 1956) during the vulnerable basidiospore stage of the rust life cycle (Peterson, 1971). Optimum overnight minimum temperatures are also critical for wave year events (Reich et al, 2015). Long‐term climatic trends at Fort St. James, BC, a weather station located near the centre of the latitudinal range of lodgepole pine in western North America (Wheeler & Critchfield, 1985), indicate a 7℃ increase in summer overnight minimum temperatures over the period of 1895–2019 (V. Foord, pers comm., June 2, 2020).…”