Impact of Windblow on the Structure and Phytomass of Siberian Pine and Birch Forests of the Central Sikhote-Alin

The impact of windblow on the structure and phytomass of cedar and birch forest stands is assessed using the surveys of permanent test plots (PTPs) in the territory of the Sikhote-Alin Reserve located on the eastern macroslope of the Sikhote-Alin Mountain, where a partial loss of the forest stand occurred due to Typhoon Lionrock. The windblow of 2016 was a catastrophic event unprecedented in the history of the reserve. More than 9% of the forest cover of the specially protected natural area has turned into continuous windblows. The initial materials for analysis included revisions of the trial plots made before and after the windblow. The interrevision period for different objects is 8–18 years. The stock of aboveground phytomass has been determined from taxation data using regional allometric equations. The windblow decreased the average stock of stone pine forests from 552 to 298 m³ ha^–1, and birch forests decreased from 253 to 163 m³ ha^–1. The total increase for stone pine and birch forests was 6.2 and 5.5 m³ ha^–1 year^–1, respectively, and the loss was 13.6 and 9.8 m³ ha^–1 year^–1, respectively. The average values of the phytomass stock are 291 t ha^–1 for cedar plantations and 210 t ha^–1 for birch plantations. Biomass stocks of birch forests decreased by 35% and cedar forests decreased by 44% as a result of windblow. A carbon stock of 150 t C ha^–1 can be considered the maximum carbon capacity of phytomass for stone pine forests of the middle and upper altitudinal zone, relative to which the storage potential of disturbed forests of this formation should be calculated. Spruce, fir, and cedar are conifers less resistant to windblow. For aspen and flat-leaved birch, the effect of the typhoon enhances their natural loss from the stand. The most resistant species were maples, Amur linden, and larch.