**3.3. Spectroradiometer measurements**

of vegetation heterogeneity related to species distribution, phenological stage, and leaf

Depending on the size and shape of the leaf, different cork borers of variable size between 2.5 and 8.5 cm diameter were used to clip a leaf disk from the central and widest portion of the

**Figure 3.** Photographs of leaf sampling process. (a) Collecting leaves using the telescopic pruner (b) climbing trees (c)

All leaf disks were clipped from the midpoint of the leaves since it has been documented that it is the best position from which to take chlorophyll readings [37]. Three readings were taken from each disk using a portable SPAD-502 chlorophyll meter at different positions of each leaf

telescopic pruner 9 m long (d) climbing trees techniques and (e) canopy towers in the study area.

disk, and a mean index value was used in further analysis.

structure. (Detailed information about the sampled process can be found in Ref. [62].)

58 Tropical Forests - The Challenges of Maintaining Ecosystem Services while Managing the Landscape

**3.2. Chlorophyll meter readings**

leaf blade, avoiding the major veins (**Figure 3**).

Reflectance and "trans‐flectance" (a term used in this study to describe the measurement of "double" transmittance) were measured for each leaf disk using an ASD FieldSpec Hand‐ Held‐2 spectroradiometer (Analytical Spectral Devices Inc., Boulder, CO, USA). This instru‐ ment provides a wavelength range of 325–1075 nm with a resolution of full width at half maximum of 3.5 nm and sampling interval of 1 nm. The spectrometer is attached with a plant probe to an internal 4.05 W halogen light source and a leaf clip that includes rotating head with both white and black reference panels (**Figure 4**).

**Figure 4.** Leaf samples and clipped disks from plants of different species and health status. The last photo shows the SPAD‐502 meter.
