Why Crowns? • To assess individuals, stands or watersheds • To indicate vigor and growth potential • To help measure net primary production • To determine basic structural architecture of forests • To assess affects on understory flora and fauna
Why Crowns? • Health is reflected in crowns • Specialists look for • Damage from insects or diseases to foliage, branches, or stem • Dieback • Cankers, wounds • Survival and growth
1) 2) 3) Use Of Crown Data
FIA Crown Classification • Consistency, repeatability • Among field people • Among crews • Among states, regions • MQO’s • Certification
Size Classes of Trees • Seedlings • >1 inch DBH and 6 inches (conifer) or 1 foot (hardwood) tall • No P3 variables • Saplings • 1 inch to 4.9 inches DBH • Several variables • Trees • 5.0 inches + DBH • Several variables
FIA Plot Configuration 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 (crown) 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, saplings • Normal foliage Individual leaves have <50% of the surface area affected by a damage agent.
Definitions, saplings • Abnormal foliage • Individual leaves have >50% of the surface area affected by a damage agent. • Note, for saplings, foliage missing from dieback areas is considered abnormal--more later.
Overstory Canopy Zone • The area delineated by the average live crown length used to determine uncompacted live crown ratio for overstory trees. • The bottom of the zone is the average height of the live crown bases. • The top of the zone is the average height for the live crown tops.
Crown Measurements Require: • A calibrated eye • 2 Certified crown raters working as a crew • A positive attitude • Good weather and daylight
½ to 1 tree length away Grade level or upslope 90o Viewing the Crown
Viewing the Crown DON’T stand under the tree to make your ratings. DON’T stand at 180o from your partner.
Crown Variables • Saplings • Uncompacted live crown ratio • Crown light exposure • Crown position • Vigor class
Codes • Crown Light Exposure • Codes: 0 to 5 • Crown Position • Codes: 1 – 4 • Sapling Vigor • Codes: 1 - 3
Uncompacted Live Crown Ratio, Saplings What is UNCOMPACTED LIVE CROWN RATIO? • The percentage of ACTUAL live tree length supporting live foliage that is effectively contributing to tree growth and maintenance.
X X Y Uncompacted Live Crown Ratio X/Y(100)
Ignore dieback when determining the length of the live crown. Uncompacted Live Crown Ratio
Uncompacted Live Crown Ratio, Saplings • Determine the live top of the tree (dieback & dead branches excluded) • Determine the base of the live crown (include the foliage on the lowest foliated “twig”; ignore any “sprigs”) • Determine the ACTUAL LENGTH of the tree • Determine the ratio of the live crown height to the actual live tree length • Agree on the best answer with your partner or average and record
Sapling Uncompacted Live Crown Ratio X Y X/Y(100)
Sapling Uncompacted Live Crown Ratio X X/Y(100) Y Remember to use ACTUAL LENGTH when determining uncompacted live crown ratio.
Sapling Uncompacted Live Crown Ratio 35% 50% 75% Include leafed twigs Exclude sprigs
Sapling Uncompacted Live Crown Ratio 65% 15% 15% Include dieback in actual length Include leafed twigs Exclude sprigs
Sapling Uncompacted Live Crown Ratio All epicormic sprigs; crown gone due to damage/dieback ULCR = 00
Crown Light Exposure • The number of sides (the top is a side, too) of a tree crown that would receive sunlight if the sun were directly overhead.
Crown Light Exposure • Divide the sapling/tree vertically into 4 sides • Divide the crown in such a way that as many sides as possible receive full light • To qualify a side must have an ULCR of 35% or more and the entire side (25% of the crown circumference) must receive full light • Count the number of sides that would receive light from directly overhead • Add 1 for the top if it receives any light • Trees with an ULCR of <35% can only have an exposure of 0 or 1
Crown Light Exposure In this case, the code for exposure would be 2
3 1 2 0 4 5 Crown Light Exposure
25% Code as 1 Crown Light Exposure
Sapling/Tree Crown Position • The relative position of each tree in relation to the main overstory canopy
Sapling/Tree 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)
Overstory Canopy Zone >50% crown cover 1 2 2 2 2 2 3 3
<50% crown cover All coded 4 Overstory Canopy Zone (Most will be coded 5 for crown light exposure)
<50% crown cover, > 1 acre in size Scattered Clumped Overstory Canopy Zone All coded 4 (Most will be coded 5 for crown light exposure)
Sapling Vigor Class - Factors • Uncompacted live crown ratio (as before) • Dieback • Must occur on the upper 50% and outer portion of the crown to be counted • Qualifies as “damaged foliage”, i.e. the foliage that would have been there contributes to the percentage of damaged foliage • Damaged foliage • 50% damage on each individual leaf • Judged as a percentage of all the foliage • Normal foliage is the inverse percentage
Sapling Vigor Class Assigned to all tally saplings to assess health and vitality • Vigor Class 1 • Must have ULCR of 35% or more • Must have less than 5% dieback • Must have 80% or more normal foliage (<20% damaged) • Vigor Class 2 • Can have any ULCR • Normal foliage from 21-100% • May or may not have dieback • Vigor Class 3 • Can have any ULCR • Must have 20% or less normal foliage
Sapling Vigor Class 1 50% 35% ULCR 35% or more, < 5% dieback, >80% normal foliage
Sapling Vigor Class 3 15% Any ULCR, Any dieback, <20% normal foliage
Sapling Vigor Class 2 15% 65% Any ULCR, <80% dieback, 21-100% normal foliage
Sapling Uncompacted Live Crown Ratio ULCR: 75% Vigor Class: 1