Hail damage to a new white spruce and lodgepole pine plantation in central British Columbia

Abstract

Hail, bane of the agriculturist and insurance adjuster, is rarely noted as a cause of damage to forest trees. Yet, when severe hailstorms occur, damage to forest vegetation may be both dramatic and serious. We report here on the immediate effects of one hailstorm on recently planted white spruce (Picea glauca (Moench) Voss) and lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) trees near the village of Upper Fraser in central British Columbia. ObservationsA drop in temperature from 65OF to 45°F immediately preceded the storm which occurred at 1630 on 23 July, 1972. Hailstones from one to one-and-a-half inches in diameter, driven by strong southwest winds, pelted down continuously for about 10 minutes causing. substantial damage to aluminum roofs and other property in Upper Fraser. The swath of the storm was over 5 miles wide; its length was undetermined.The opportunity to make the observations and comparisons reported here resulted from the "mixed blessing" of having Canadian Forestry Service regeneration research plots directly in the path of the storm. The plots contained planted spruce and pine trees of three ages: 4-year-old transplants (2-1 stock planted in fall, 1970). 3-year-old seedlings (2-0 stock planted in spring, 1971 ) and 2-year-old seedlings (2-0 stock planted in spring, 1972). The plots had received various site preparation treatments and covered a range of site types. In some plots, the seedlings had been stratified into three size classes at the time of plantingsmall, medium and large.The plots were inspected immediately after the storm, and in mid-September the degree of defoliation, presence of stem lesions and death of terminal buds or leaders were assessed. Defoliation was assessed as heavy if the loss was greater than 50% for pine or 30% for spruce. (The different criteria were adopted because of greater defoliation on pine. The effect is to exaggerate the defoliation of spruce compared to pine and to under-emphasize the difference between them. In retrospect, 50% should have been adopted as the criterion for both species.) Lesions were recorded only if they were on the main stem and were greater than 3-cm long. Over 1500 trees of each species were assessed.Ground vegetation was flattened by the storm and within a week. dead and wilted leaves resembled the effect; of autumn frosts. However, within a month, the shrubs had made a vigorous recovery. Defoliation, stem lesions and broken branches and leaders were evident on most smaller trees and the litter of twigs covering roads adjacent to mature standing timber showed that large trees had not escaped damage. Damage to leaders in a 5-year-old spruce plantation was similar to that resulting from a serious outbreak of spruce weevil.Of 3122 trees examined, 14% were undamaged and 2 % were killed by hail; the rest suffered varying degrees of damage. Typical damage was defoliation, stem lesions which were confined to the windward side of stems, and dead leaders usually caused by extensive wounding of the bark (Figs. 1 and 2). ama age t...

Foliar habit, tolerance to defoliation and their link to carbon and nitrogen storage

“…). Abiotic disturbances like frost, wind, severe drought and hail are other important agents of defoliation in temperate forests (Grayburn ; Dobbs & McMinn ; Ozolincius & Stakenas ; Lorenz & Becher ), which also appear to cause more defoliation in deciduous than in evergreen species (Lorenz & Becher ). In cases of intense and unpredictable defoliation, herbivory tolerance is thought to be the most efficient strategy to adopt (van der Meijden, Wijn & Verkaar ; Haukioja & Koricheva ).…”

“…The fast leaf economics strategy of deciduous species, associated with low toughness and high nutrient concentration and specific leaf area (SLA; Mooney & Gulmon 1982;Wright et al 2004), certainly makes leaves more susceptible to herbivory (Chabot & Hicks 1982;Pringle et al 2011). Abiotic disturbances like frost, wind, severe drought and hail are other important agents of defoliation in temperate forests (Grayburn 1957;Dobbs & McMinn 1973;Ozolincius & Stakenas 1996;Lorenz & Becher 2012), which also appear to cause more defoliation in deciduous than in evergreen species (Lorenz & Becher 2012). In cases of intense and unpredictable defoliation, herbivory tolerance is thought to be the most efficient strategy to adopt (van der Meijden, Wijn & Verkaar 1988;Haukioja & Koricheva 2000).…”

Effects of Damaged Levels and Pruning of Peach and Japanese Apricot Trees by Hailstorms on the Performance

“…Increased damaged levels substantially lead to reduced shoot diameter in years 2-4. Previous studies reported that recovery of the shoot growth of peach and apple fruit trees or pine trees was not completely occurred with leaf injury over 50% from hail in the following season due to the reduced synthesis of assimilates from lack of sources [16,23,24]. The number of shoots and shoot length of Japanese apricot trees showed similar trends to the peach trees, responding to the levels of DF and DF + IP in years 2-4 (Table 3).…”

An experimental approach for crown to whole-canopy defoliation in forests

“…Among the numerous forms of disturbance mimicked experimentally, canopy defoliation stands out as an important source of disturbance in forest ecosystems that has rarely been represented in largescale manipulation experiments despite its massive global impact and increasing extent (Anderegg et al 2015, Fei et al 2019. Defoliation can occur as a result of herbivory, pathogens, or through mechanical means (e.g., hailstorms or hurricanes; Dobbs andMcMinn 1973, Shiels et al 2014). Most extensive and severe defoliation events are related to insect pests, and patterns of defoliation timing and intensity vary, with cyclical, outbreak, and background herbivory all common in nature (Kautz et al 2017).…”