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基于野外采样、定点观测和室内实验,研究了青海黄土丘陵区不同退耕还林模式生态效应,结果表明相同林龄(8 a)的不同退耕还林模式(5种)水土效应:云杉桦树混交>桦树>云杉沙棘混交>云杉>沙棘>农田;生物效应:云杉桦树混交>沙棘>桦树>云杉>云杉沙棘混交>农田;小气候效应:云杉桦树混交>桦树>云杉沙棘混交>沙棘>云杉>农田。研究结果同时表明,相同退耕还林模式(沙棘)生产力效应随着林龄的增加而增加:10 a沙棘>8 a沙棘>3 a沙棘。
Based on field sampling, fixed-point observation and laboratory experiments, the ecological effects of different models of returning farmland to forestry in Qinghai loess hilly region were studied. The results showed that the soil and water conservation effects of different models of returning farmland to forest (five species) Mixed> birch> spruce hybrid> spruce> seabuckthorn> farmland; biological effect: spruce birch mixed> seabuckthorn> birch> spruce> spruce mixed> farmland; microclimate effect: spruce birch mixed> Birch> Spruce Seabuckthorn Mixed> Seabuckthorn> Picea> Farmland. The results also showed that the productivity of the same model (Seabuckthorn) increased with age: 10 a for sea buckthorn> 8 a for sea buckthorn> 3 for seabuckthorn.