Crown-condition classification: a guide to data collection and analysis

Abstract

The Forest Inventory and Analysis (FIA) Program of the Forest Service, U.S. Department of Agriculture, conducts a national inventory of forests across the United States. A systematic subset of permanent inventory plots in 45 States is currently sampled every year for numerous forest health indicators. One of these indicators, crown-condition classification, is designed to estimate tree crown dimensions and assess the impact of crown stressors. The indicator features eight tree-level field measurements in addition to variables traditionally measured in conjunction with FIA inventories: vigor class, uncompacted live crown ratio, crown light exposure, crown position, crown density, crown dieback, foliage transparency, and crown diameter. Indicators of crown health derived from the crown data are intended for analyses at the State, regional, and national levels, and contribute to the core tabular output in standard FIA reports. Crown-condition measurements were originally implemented as part of the Forest Health Monitoring (FHM) Program in 1990. Except for crown diameter, these measurements were continued when the FIA Program assumed responsibility for FHM plot-based detection monitoring in 2000. This report describes in detail the data collection and analytical techniques recommended for crown-condition classification.

Diversity and density of the EM fungal community present in high elevation Fraser fir forests of Great Smoky Mountains National Park

“…The management treatments were based on naturally occurring age classes: 1) low regeneration plots, defined as containing <10% of plot areas with Fraser fir seedlings and no sapling regeneration; 2) sapling plots, defined as stands with trees >1.37 m tall and <5.0 cm diameter at breast height (dbh=1.37 m), with up to 50 % of plot containing saplings and 50% canopy closure; and 3) mature stands, with trees >15.0 cm dbh and complete enclosed canopy cover. All Fraser fir trees within the plots were numbered and the dbh was measured on the uphill side of each tree using previously defined methods (Schomaker et al 2007). This data provided tree density, maturity and canopy closure information that are believed to impact occurrence of fungi.…”

Prior height, growth, and wood anatomy differently predispose to drought-induced dieback in two Mediterranean oak speciesk

“…For each sampled tree, the proportion of crown cover was estimated to the nearest 5 % (Schomaker et al 2007). Since estimations of crown cover vary among observers and places, the data were always recorded by the first author, who compared every tree with a reference tree with the maximum amount of foliage at each site.…”

Mapping Robinia Pseudoacacia Forest Health Conditions by Using Combined Spectral, Spatial and Textureal Information Extracted From Ikonos Imagery

“…Within each of 375 subplots, three average Robinia pseudoacacia trees were selected and evaluated according to the USFS (United States Forest Service) Crown Condition Classification Guide (CCCG) standard (Schomaker et al, 2007). These CCCG indicator data were then averaged from the five subplots for each plot and each indicator was classified into one class from the three vigor classes based on a range of values according to Wang et al (2015b).…”