Vertical stratification of leaf physical traits exerts bottom-up pressures on insect herbivory in a sugar maple temperate forest

Do vertical gradients in temperate forest structure insect herbivore communities?  We tested the hypothesis that the increase in light intensity from understory to forest canopy level drives differences in leaf physical traits and budburst phenology that impact insect herbivores and thus play a role in structuring both herbivore communities and the leaf damages they cause. Twelve sugar maple (Acer saccharum) sites were monitored in southern Quebec, examining insect herbivore patterns from understory to the shaded and sun canopy over the summers of 2020, 2021, and 2022. Additionally, we recorded leaf physical traits, temperature, humidity, and sun exposure. Our findings revealed that leaf thickness increased along the vertical gradient in 2021, making leaves less favorable to herbivores in the canopy level. Accordingly, we recorded a consistent decrease in insect herbivory damage rates from the understory to the shaded canopy and sun canopy in 2020 and 2021, driven by leaf cutters, skele..., Study site and plant species
We conducted our sampling at the Kenauk Nature property, located in southwestern Quebec, Canada (45°42'N; 74°53'W). The property spans two regions from the Outaouais river valley to the Laurentian Mountains. Based on the provided domains map by the Quebec Ministry of Forests it is in a maple/bitternut hickory domain of temperate deciduous forest (Quebec Ministry of Forests 2023). To consider the variation in insect herbivory throughout the growing season, three sampling sessions were conducted at the end of June, end of July, and middle of August in 2020, 2021, and 2022. During each session, we sampled the same 12 sites, each spaced more than 15 meters apart and tree species composition was relatively uniform in all sites. These sites were selected based on the similarity in tree size and safety considerations for climbing. Each site comprised one mature sugar maple tree and one sapling. We collected samples from both the sunlit and shaded canopy levels of t..., , We have submitted our raw data including Insect herbivory damages on leaves, recorded environmental factors, and measured leaf traits in 2020 and 2021(**Leaf damage.trait.2020.2021.csv**), insect herbivore specimen information collected in 2022 (**herbivore.guilds.22.csv**), recorded budburst phenology raw data for all sampled trees in 2022 (**sugar.maple.budburst.22.csv**), data needed for leaf trait correlation with leaf herbivory damages in RDA analysis (**rda.dam.trait.21.csv**), four data sets created out of *Leaf damage.trait.2020.2021.csv* for illustrating line graphs for insect herbivory damages variation thorough time and between tree strata for 2020 and 2021 (**Av.dam.sampling.20.csv, Av.dam.sampling.21.csv, Av.dam.20.strata.csv, Av.dam.21.strata.csv**) and R script (**Damage.trait.20.21.R**).

### Descriptions

#### **Leaf damage.trait.2020.2021.csv**

* *Month*: Sampling performed in 1 = June, 2= July and 3=August
* *Site*: each selected 12 sites includes one mature sug...