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Crown-Condition Classification Tutorial. (Revised January 2008). Why Crowns?. To assess tree vigor and growth potential Early warning sign of tree health deterioration Crowns form the structural architecture of forests Crowns influence understory flora and fauna
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Crown-Condition Classification Tutorial (Revised January 2008)
Why Crowns? • To assess tree vigor and growth potential • Early warning sign of tree health deterioration • Crowns form the structural architecture of forests • Crowns influence understory flora and fauna • To assess individuals, ecosystems, states, regions
Crown Variables • Uncompacted Live Crown Ratio • Crown Position • Crown Light Exposure • Crown Density • Crown Dieback • Foliage Transparency • Sapling Vigor Class
Size Classes of Trees • Seedlings • <1.0-inch DBH/DRC • Saplings • 1 inch to 4.9 inches DBH/DRC • Trees • 5 inches + DBH/DRC
Crown Variables • Both Saplings and Trees • Uncompacted Live Crown Ratio • Crown Position • Crown Light Exposure • Trees Only • Crown Density • Crown Dieback • Foliage Transparency • Saplings Only • Crown Vigor Class
FIA Plot Configuration Macroplot-trees Subplot-trees Microplot-saplings
Definitions • Live branch Woody lateral growth supporting foliage and larger than 1 inch at the base just above the swelling where it joins the main stem.
Definitions • Twig Woody lateral growth with secondary branching and less than 1 inch in diameter at the point of attachment to a branch or crown stem.
Definitions • Sprig Woody or non-woody lateral growth without secondary branching and less than 1 inch.
Definitions • Snag branch Dead upper crown branches without fine twigs.
Definitions • Epicormic branches Woody or non-woody lateral growths, usually on the bole or crown stem and initiated by sudden exposure or loss of crown stem.
Definitions • Crown Outline Outline Exclude abnormally long branches
Definitions Crown Top • Crown Top
Definitions • Obvious Live Crown • Obvious Live Crown Base Obvious Live Crown Crown Base
Crown Base Definitions • Live Crown Base, Saplings
> 5 feet Definitions Point 1 • 5-ft Rule Point 2
Definitions • 5-ft Rule Point 1 < 5 ft Point 2
Viewing the Crown Quality Crown Measurements Require… • A calibrated eye • A positive attitude • Good weather and daylight • 2 certified crown raters working as a crew
90o Viewing the Crown ½ to 1 tree length away View from grade level or upslope
Viewing the Crown • Separate the subject from other trees • Rate the whole crown, not just the easiest part to see
Viewing the Crown DON’T stand under the tree to make your ratings. DON’T stand at 180o from your partner.
Field Aid • Useful for…Live Crown RatioCrown DensityFoliage Transparency
Crown Variables • Both Saplings and Trees • Uncompacted Live Crown Ratio • Crown Position • Crown Light Exposure • Trees Only • Crown Density • Crown Dieback • Foliage Transparency • Saplings Only • Crown Vigor Class
X X Y Y ULCR = X/Y(100) Uncompacted Live Crown Ratio
Uncompacted Live Crown Ratio • Determine the LIVE TOP of the tree (dieback & dead branches excluded) • Establish the OBVIOUS LIVE CROWN BASE • Determine the ACTUAL LENGTH of the tree (same as defined in the Phase 2 field guide) • Express the length of the Obvious Live Crown as a PERCENTAGE of the Actual Length • Agree on best answer with your partner or average and record to the nearest percent
Uncompacted Live Crown Ratio For trees: The Obvious Live Crown includes foliage and branches down to the lowest foliage of the lowest 1-inch branch.
Uncompacted Live Crown Ratio For trees: The 5-foot, 1-inch rule <5 feet; include New Live Crown Base >5 feet; exclude >1 inch
? ? ? ? >5 feet, >1 inch ULCR = 50 - 75%? Uncompacted Live Crown Ratio
35% 50% 75% Include leafed twigs Exclude sprigs Uncompacted Live Crown Ratio For saplings: The Obvious Live Crown includes twigs, but not sprigs.
Uncompacted Live Crown Ratio X X/Y(100) Y Obvious Live Crown (X) excludes dieback. Actual Length (Y) includes dieback.
Uncompacted Live Crown Ratio Epicormic branches: If tree or sapling crown contains only epicormics, ULCR = 00
Crown Position • The relative position of each tree in relation to the main overstory canopy Four Codes: • Superstory • Overstory • Understory • Open Grown
Overstory Canopy Zone Average Live Crown Lengths of overstory trees
1 2 2 midpoint 2 2 2 3 3 Crown Position
Crown Position Open Canopy: All saplings and trees coded 4 4 4 4 4
Crown Position <50% crown cover, > 1 acre in size Scattered All coded 4 Clumped
Crown Position • 2 Conditions (> 1 acre in size) • >50% crown cover • 1=Superstory (Never for saplings) • 2=Overstory • 3=Understory • <50% crown cover • 4=Open grown (all saplings/trees)
Crown Light Exposure The number of sides of a crown (including the top) that receive sunlight when the sun is directly overhead.
Crown Light Exposure In this case, the code for exposure would be 2
ULCR = 25% Code as 1 Crown Light Exposure
3 1 2 0 4 5 Crown Light Exposure
Crown Variables • Both Saplings and Trees • Uncompacted Live Crown Ratio • Crown Position • Crown Light Exposure • Trees Only • Crown Density • Crown Dieback • Foliage Transparency • Saplings Only • Crown Vigor Class
Codes for 5-percent Classes • Crown density, crown dieback and foliage transparency… • 00 No Crown • 05 1-5% • 10 6-10% • 15 11-15% • … … • 99 96-100%
Crown Density • The amount of crown branches, foliage, and reproductive structures that block light visibility through the crown
plywood Density: 100% Crown Density