Increasing summer temperatures are driving changes in both insect and tree phenology, especially in arctic regions. Tree growth and productivity have been in decline for many tree species in North America (van Mantgem et al. 2009). Warmer temperatures increase vapor pressure deficit (VPD) and water-use by trees, which may limit tree growth. Trophic interactions, however, can complicate the impacts of climate change on forests, making combined impacts difficult to predict (Rosenblatt and Schmitz 2016). Outbreaks of herbivorous insects have been shown to significantly affect plant performance (Yang 2012). The magnitude of these insect outbreaks can increase because of warmer winter temperatures that improve overwintering survivorship (Kreyling 2010) and warmer spring conditions that enhance herbivore reproduction (Ayres and Lombardero 2000). Furthermore, the damage caused by herbivores on plants can be magnified in the summer by increases in VPD due to increased temperatures and low water availability (Anderegg et al. 2015).

中文翻译：

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昆虫的取食位置决定了树木中生物和环境压力源之间的相互作用。

夏季气温的升高推动了昆虫和树木物候的变化，尤其是在北极地区。北美许多树木的树木生长和生产力一直在下降（van Mantgem等，2009）。较温暖的温度会增加树木的蒸气压亏缺（VPD）和用水，这可能会限制树木的生长。然而，营养相互作用可能使气候变化对森林的影响复杂化，使得综合影响难以预测（Rosenblatt and Schmitz 2016）。食草昆虫的爆发已被证明会严重影响植物的生长性能（Yang 2012）。这些昆虫爆发的幅度可能会增加，原因是冬季气温升高，改善了越冬的存活率（Kreyling，2010年），春季气候条件改善，从而提高了草食动物的繁殖能力（Ayres和Lombardero，2000年）。