Abstract Detail

Ecology

Holkeboer, Noah [1], Polaski, Steven [2], May, Brendan [2], Foy, Nicole [3], Greer, Gary [1].

Strengths and limitations of using photographs to study tree architecture: destructive confirmation and pilot study of four species.

To our knowledge, all previously-published research regarding tree architecture and allometry is based on direct measurements that require destruction of limbs or entire trees. This approach produces precise measurements, but also limits the scale and type of study that is possible. Destructive methods make large-scale (e.g., forest plot) studies expensive in labor, time, equipment, and permitting, and make longitudinal studies impossible. In an effort to broaden the scope of inquiry regarding tree architecture, we tested the utility of using scaled photographs. We compared data and estimates of hydraulic efficiency and structural support acquired from photographs versus data acquired from direct, destructive measurements from a 23-meter Acer rubrum. As expected, we found that measurements acquired from photographs of the entire tree corresponded to direct measurements only at a coarse-grained level and therefore have limited utility. In contrast, measurements acquired from photographs focused (laterally) on each node correspond very closely to direct measurements; however, surprisingly, correspondence was weakest for large nodes, trending towards over-estimation. Nonetheless, linear-regression models of the allometry of hydraulic efficiency per Murray's Law and structural support per the Uniform Stress Model were nearly identical in slope and y-intercept such that the same conclusions would be drawn from each dataset. We also used photographs to study the architecture of four tree species: Acer saccharum, Quercus rubra, Fagus grandifolia, and Ginkgo biloba. We took two photographs (i.e., the entire tree and its basal node) of thirty individuals ranging in stature for each species. Data acquired from these photographs were used to estimate hydraulic efficiency and structural support as above. The resulting linear regressions were characterized by r-square values above 0.95 that distinguished species-specific optimizations as well as intra-specific optimizations associated with increasing size. We conclude that photographs are a useful tool for studying tree architecture across large scales of space and time; however, biases inherent with this indirect method of data collection impose limits on its application.

1 - Grand Valley State University, Biology, 1 Campus Drive, Kindschi Hall 3319, Allendale, MI, 49401, USA
2 - Grand Valley State University
3 - n/a

Keywords:
allometry
hydraulic efficiency
structural support
tree
photography
non-destructive.

Presentation Type: Oral Paper
Session: ECO1, Ecology: Phylogeny, Disturbance, and Tree Architecture Over Large Spatial Scales
Location: /
Date: Tuesday, July 20th, 2021
Time: 11:00 AM(EDT)
Number: ECO1005
Abstract ID:469
Candidate for Awards:None