Ice damages of coniferous trees in hemiboreal forests in
Transcription
Ice damages of coniferous trees in hemiboreal forests in
Ice damages of coniferous trees in hemiboreal forests in context of climatic changes: case study in Latvia Aris Jansons, Endijs Baders, Juris Rieksts-Riekstins, Una Neimane aris.jansons@silava.lv Ice damages in forest (http://apollo.lsc.vsc.edu) Average number of days with ice Ice damages in forest 6 5 4 3 2 1 0 Liepaja Aluksne 10 11 12 1 2 3 Month of the year 4 LVĢMC (Krauklis, 2006; http://chalk.richmond.edu) There is no reason to believe, that frequency of ice events will decrease in future due to climatic changes Ice damages in forest Ice damages: • rare and difficult (impossible) to predict • ice-load effect often mixed with wind-load and can be mixed with snow load, therefore generalization of results hardly possible • measurement period stretched in time – additional weight piled on trees in a form of snow Material & Methods Ice storm in the end of December 2012 Sample plots placed in the most affected forest massive in 163 stands (98 pine, 51 spruce and 14 mixed) Material & Methods Stands were selected randomly within groups determined by age classes (from 20 to 120 years), forest types (most common on dry, drained and wet soils) time after last thinning (up to 3 years and more than 3 years). Ten circular sample plots (200m2) were systematically placed within each stand For each tree height, diameter, height of green crown were measured Damage assessment: for broken trees – height of standing trunk, for bent trees – height and angle of the curve or angle of slope. Material & Methods Results Ice damages, independently from dominant tree species, were found for 27% of trees. Results Dominant tree species were not affecting the type of damage: mostly broken tops – 18% of trees. Results 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Spruce Mixed Sl Nd Mrs Mr-ln Mr Ln Ks Dms Dm As Ks Dm As Vrs Vr Kp Dms Dm As Not damaged Old damage Bent Broken Pine Forest type had a significant effect on proportion of damaged trees (22-41%) as well as type of damage Bent trees were detected in all forest types and the proportion ranged from 4 to 29% Results Amount and type of damages was significantly affected by tree dimensions Results Broken Broken in green crown Broken below green crown Uprooted Stand age had notable influence on proportion of damaged trees and type of damages. Thinning has a statistically significant effect on proportion of damaged trees – it was higher after the thinning in stands of both species Thank You! Research was carried out in Forest Competence Centre (ERAF) project „Methods and technologies for increasing forest capital value” (No. L-KC-11-0004) Aris Jansons, Endijs Baders, Juris Rieksts-Riekstins, Una Neimane & Andis Adamovics, Juris Katrevics, Raitis Rieksts-Riekstins aris.jansons@silava.lv