Sapling Crown Vigor 

 for All Species 



Good Average Poor 



Crown Vigor Class 



(saplings 1.0-4.9 in. DBH) 



Hardwood/Softwood 

 Sapling Vigor 



Good 



Poor 



Average 



Sapling Vigor 



(saplings 1 .0-4.9 in. DBH and larger) 



tion by indirectly assessing its 

 ability to capture light and 

 produce carbohydrates by 

 photosynthesis. Crown condi- 

 tion indicators used in this re- 

 port are sapling crown vigor, 

 crown density, crown dieback, 

 and foliage transparency. 



Crown density 



A 2-dimensional viev» of 

 foliage, branches, and 

 reproductive structures {%) 

 tfiat obstruct ligtit penetra- 

 tion througfi tfie crown. 

 Example below has a 

 density of about 50% 



Crown dieback Foliage transparency 



The percentage of branch A measure of sunlight (%) 

 tips dying back from the filtering through needles 

 crown edge. Normal death j and leaves in the crown, 

 by shading is not counted. 



Sapling Crown Vigor 



Sapling crown vigor was 

 evaluated for 79 saplings. 

 High ratings in the good and 

 average categories (vigor class 

 1 and vigor class 2) indicate more foli- 

 age area available for photosynthesis. 

 Across all species, the sum of good and 

 average sapling vigor was 94%; only five 

 saplings (6%) had poor vigor (vigor class 

 3). Almost twice as many hardwood sap- 

 lings had good vigor compared to soft- 

 wood saplings, but the sum of good and 

 average vigor for both was >90%. Over 

 90% of all saplings in the Pilot Study and 

 California 1992-95 plots had high (good 

 + average) crowm vigor ratings. 



Crown Density 



Crown density represents the relative 

 amount of foliage, branches, and repro- 

 ductive structures that obstruct skylight 

 visibility through the crown. Young emd 

 old trees with vigorous growth generally 

 have full crowns and high density val- 

 ues — a condition indicating more foliage 

 area available for photosynthesis. In- 

 cluding all species and trees, 96% of Pi- 

 lot Study trees had high (good + average) 

 crowm density ratings. Hardwoods had 

 a lower percentage of good ratings but a 

 larger percentage of average ratings. 

 These findings were similar for all trees 

 and species by state. The lower percent- 

 age of good ratings in Oregon probably 

 reflects lower vigor of older stands 

 sampled there. 



Crown density, crown dieback, and foliage 

 transparency raljng example. 



Monitoring — 70 



