Functional leaf and stem traits of the Oaks of the Americas

Leaf and stem trait data: Measured interspecific variation of Quercus (L.) - totaling 15+ functional traits for 135* American oak species. Our goal was to hand-measure/characterize as many North American species as possible. Measurements include: (1) specific leaf area (SLA, mm2 mg), an important leaf economic spectrum (LES) trait associated with leaf lifespan, resource acquisition, and nutrient use (Wright et al., 2004; Reich, 2014), (2) perimeter per unit leaf area (PLA, cm−1), a leaf trait that increases with degree of lobing and decreases with leaf size and is associated with hydraulic conductance and boundary layer resistance for all species (Sack et al., 2003; Kaproth and Cavender‐Bares, 2016), (3) total length of major veins per area (cm−1), associated with leaf hydraulic function (Sack and Scoffoni, 2013), (4) leaf length (mm), (5) petiole length (mm), and (6) stem specific density (g·cm−3), associated with mechanical strength and drought tolerance (Cornelissen et al., 2003; Kunstler et al., 2015). Specimens from sunlit branches were pressed and dried alongside samples collected for herbarium specimens as part of the Oaks of the Americas Project (Hipp et al., 2018).

叶与茎功能性状数据集：测定栎属（Quercus，L.）的种间变异——涵盖135余种北美栎类物种的15项以上功能性状。本研究旨在尽可能多地对北美栎类物种开展手工测定与性状表征。
本次测定的性状包括：
1. 比叶面积（specific leaf area, SLA，单位：mm²·mg⁻¹），属于重要的叶经济谱（leaf economic spectrum, LES）性状，与叶片寿命、资源获取及养分利用效率密切相关（Wright等，2004；Reich，2014）；
2. 单位叶面积周长（perimeter per unit leaf area, PLA，单位：cm⁻¹），该性状随叶片裂片程度升高而增大、随叶片尺寸增大而减小，且与所有物种的水力导度及边界层阻力相关（Sack等，2003；Kaproth与Cavender-Bares，2016）；
3. 单位叶面积主脉总长度（单位：cm⁻¹），与叶片水力功能相关（Sack与Scoffoni，2013）；
4. 叶片长度（单位：mm）；
5. 叶柄长度（单位：mm）；
6. 茎部比密度（单位：g·cm⁻³），与机械强度及耐旱性相关（Cornelissen等，2003；Kunstler等，2015）。
采集自向阳枝条的标本与“北美栎类项目”（Oaks of the Americas Project，Hipp等，2018）中用于标本馆馆藏的样品一同进行压制与干燥处理。