Forest Structural Conditions

The forest structural conditions are based upon the following attributes: 
    1) tree size (dbh);
    2) percent canopy cover (or percent grass/forb cover); and, 
    3) number of canopy layers. 
These attributes have the following values:

Tree Size (dbh)

Shrub/Seedling

 <1"   

 <2.5 cm

Sapling/Pole

 1-9"   

 2.5-24 cm

Small Tree

 10-14"   

 25-37 cm

Medium Tree

 15-19"   

 38-49 cm

Large Tree

 20-29"   

 50-75 cm

Giant Tree

 > 30"   

 > 76 cm

Percent Canopy Cover

Open

 10-39%

Moderate

 40-69%

Closed

 70-100%

Number of Canopy Layers

Single Story

 1 stratum

Multi-story

 2 or more strata

The above attributes have been combined into the following structural conditions:

1) Grass/Forb - Open
FOREST1.JPG (44524 bytes) Grass/Forb dominated with <70% coverage by grasses and forbs. Shrubs and small seedlings may be present, but do not dominate stand, (seedlings < 10% canopy cover), and there can be remnant trees (trees remaining from the previous stand) that can provide <10% canopy cover.


2) Grass/Forb - Closed
FOREST2.JPG (51683 bytes) Grass/Forb dominated with >70% coverage by grasses and forbs. Shrubs and small seedlings may be present, but do not dominate stand, (seedlings < 10% canopy cover), and there can be remnant trees (trees remaining from the previous stand) that can provide <10% canopy cover.


3) Shrub/Seedling - Open
FOREST3.JPG (48230 bytes) Seedlings are large enough to add structure to the stand but are small enough that the structure is similar to shrubs and may have remnant trees (trees remaining from the previous stand) that can provide <10% canopy cover. There is <70% cover of shrubs or seedlings. Tree size has <1" dbh, and there is only a single canopy stratum.


4) Shrub/Seedling - Closed
FOREST4.JPG (80067 bytes) Seedlings are large enough to add structure to the stand but are small enough that the structure is similar to shrubs. Remnant trees (trees remaining from the previous stand) can provide <10% canopy cover. There is >70% cover of shrubs or seedlings. Tree size has <1" dbh, and there is only a single canopy stratum.


5) Sapling/Pole - Open
FOREST5.JPG (76981 bytes) The canopy is open enough that understory vegetation may be abundant. Remnant trees (trees remaining from the previous stand) can provide <10% canopy cover. There is 10-39% cover of sapling and pole sized trees. Tree size is 1"-9" dbh, and there is a single canopy stratum.


6) Sapling/Pole - Moderate

FOREST6.JPG (90670 bytes) Understory development is hampered by available light and moisture. Remnant trees (trees remaining from the previous stand) can provide <10% canopy cover. There is 40-69% cover of sapling and pole sized trees. Tree size is 1"-9" dbh, and there is a single canopy stratum.


7) Sapling/Pole - Closed
FOREST7.JPG (109163 bytes) The understory is depauperate or absent. Remnant trees (trees remaining from the previous stand) can provide <10% canopy cover. There is > 70% cover of sapling and pole sized trees. Tree size is 1"- 9" dbh and there is a single canopy stratum.


8) Small Tree - Single Story - Open
FOREST8.JPG (87520 bytes) A grass/forb or shrub understory may be present. Remnant trees (trees remaining from the previous stand) can provide <10% canopy cover. There is 10-39% cover of small trees, with <10% cover of other tree sizes. Tree size is 10-14" dbh, and there is a single canopy stratum.


9) Small Tree - Single Story - Moderate
FOREST9.JPG (118136 bytes) Some grass/forb or shrub understory may be present. Remnant trees (green trees remaining from the previous stand) can provide <10% canopy cover. There is 40-69% cover of small trees with <10% cover of other sized trees. Tree size is 10-14" dbh, and there is a single canopy stratum.


10) Small Tree - Single Story - Closed
FOREST10.JPG (136328 bytes) Grass/Forb or shrub understory minor or absent. Remnant trees (trees remaining from the previous stand) can provide <10% canopy cover. There is > 70% cover of small trees, with <10% cover of other sized trees. Tree size is 10-14" dbh, and there is a single canopy stratum.


11) Medium Tree - Single Story - Open
FOREST11.JPG (94404 bytes) A grass/forb or shrub understory may be present. Remnant trees (trees remaining from the previous stand) can provide <10% canopy cover. There is 10-39% cover of medium trees, with <10% cover of other sized trees. Tree size is 15-19" dbh, and there is a single canopy stratum.


12) Medium Tree - Single Story - Moderate
FOREST12.JPG (155803 bytes) Grass/Forb or shrub understory may be present. Remnant trees (trees remaining from the previous stand) can provide <10% canopy cover. There is 40-69% cover of medium trees with <10% cover of other sized trees. Tree size is 15-19" dbh, and there is a single canopy stratum.


13) Medium Tree - Single Story - Closed
FOREST13.JPG (164233 bytes) A grass/forb or shrub understory may be present. Remnant trees (trees remaining from the previous stand) can provide <10% canopy cover. There is >70% cover of medium trees with <10% cover of other sized trees. Tree size is 15-19" dbh, and there is a single canopy stratum.


14) Large Tree - Single Story - Open
FOREST14.JPG (113682 bytes) Grasses, shrubs, and/or seedlings may occur in the understory. There is 10-39% cover of large and/or giant size trees with <10% cover of other sized trees. Tree size is 20"-29" dbh, and there is a single canopy stratum.


15) Large Tree - Single Story - Moderate
FOREST15.JPG (200401 bytes) Some grass/forb or shrub understory may be present. There is 40-69% cover of large and/or giant trees with <10% cover of other sized trees. Tree size is 20"-29" dbh, and there is a single canopy stratum.


16) Large Tree - Single Story - Closed
FOREST16.JPG (224314 bytes) Grasses, shrubs, and/or seedlings may occur in the understory. There is >70% cover of large and/or giant trees with <10% cover of other sized trees. Tree size is 20"-29" dbh, and there is a single canopy stratum.


17) Small Tree - Multi-story - Open
FOREST17.JPG (94857 bytes) These stands have an overstory of small trees with a distinct subcanopy of saplings and/or poles. Scattered larger trees may be present but make up less than 10% canopy cover. Grass/forb or shrub understory may be present. There is 10-39% total canopy cover dominated by small trees, at least 10% or more canopy cover of 1 or more other smaller tree sizes. Tree size is 10"-14" dbh, and there are two or more canopy strata.


18) Small Tree - Multi-story - Moderate
FOREST18.JPG (121477 bytes) These stands have an overstory of small trees with a distinct subcanopy of saplings and/or poles. Scattered larger trees may be present but make up less than 10% canopy cover. Grass/forb or shrub understory may be present, but is probably limited. There is 40-69% total canopy cover dominated by small trees, at least 10% or more canopy cover of 1 or more other smaller tree sizes. Tree size is 10"-14" dbh, and there are two or more canopy strata.


19) Small Tree - Multi-story - Closed
FOREST19.JPG (138623 bytes) These stands have an overstory of small trees with a distinct subcanopy of saplings and/or poles. Scattered larger trees may be present but make up less than 10% canopy cover. Grass/forb or shrub understory extremely limited or absent. There is >70% total canopy cover dominated by small trees, at least 10% or more canopy cover of 1 or more other smaller tree sizes. Tree size is 10-14" dbh, and there are two or more canopy strata.


20) Medium Tree - Multi-story- Open
FOREST20.JPG (135933 bytes) These stands have an overstory of medium trees with a distinct subcanopy of smaller trees. Scattered larger trees may be present but make up less than 10% canopy cover. Grass/forb or shrub understory may be present, but is probably limited. There is 10-39% total canopy cover dominated by medium trees, at least 10% or more canopy cover of 1 or more smaller tree sizes. Tree size is 15"-19" dbh, and there are two or more canopy strata.


21) Medium Tree - Multi-story - Moderate
FOREST21.JPG (149882 bytes) These stands have an overstory of medium trees with a distinct subcanopy of smaller trees. Scattered larger trees may be present but make up less than 10% canopy cover. Grass/forb or shrub understory may be present, but is probably limited. There is 40-69% total canopy cover dominated by medium trees, at least 10% or more canopy cover of 1 or more smaller tree sizes. Tree size is 15"-19" dbh, and there are two or more canopy strata.


22) Medium Tree - Multi-story - Closed
FOREST22.JPG (172354 bytes) These stands have an overstory of medium trees with a distinct subcanopy of smaller trees. Scattered larger trees may be present but make up less than 10% canopy cover. Grass/forb understory may be present, but is probably limited. There is >70% total canopy cover dominated by medium trees, at least 10% or more canopy cover of 1 or more smaller tree sizes. Tree size is 15"- 19" dbh, and there are two or more canopy strata.


23) Large Tree - Multi-story - Open
FOREST23.JPG (162415 bytes) These stands have an overstory of large or giant sized trees with one or more distinct canopy layers of smaller trees. Stands > 40% cover of giant trees are classified in the "Giant, multi-storied" stage. In westside forests, stands dominated by large trees, usually have giant trees scattered in the stand, with lower numbers in eastside forests. Grass/Forb or shrub understory often present, especially in canopy gaps. There is 10-39% total canopy cover, with at least 10% or more canopy cover from large and/or giant trees and another 10% or more canopy cover from 1 or more smaller tree size classes. Tree size is 20"-29" dbh, and there are two or more canopy strata.


24) Large Tree - Multi-story - Moderate
FOREST24.JPG (204671 bytes) These stands have an overstory of large or giant sized trees with one or more distinct canopy layers of smaller trees. Stands > 40% cover of giant trees are classified in the "Giant, multi-storied" stage. In westside forests, stands dominated by large trees, usually have giant trees scattered in the stand, with lower numbers in eastside forests. Grass/Forb or shrub understory often present, especially in canopy gaps. There is 40-69% total canopy cover, at least 10% or more canopy cover from large trees with another 10% or more canopy cover from 1 or more smaller tree size classes. Tree size is 20"-29" dbh, and there are two or more canopy strata.


25) Large Tree - Multi-story - Closed
FOREST25.JPG (245751 bytes) These stands have an overstory of large or giant sized trees with one or more distinct canopy layers of smaller trees. Stands > 40% cover of giant trees are classified in the "Giant, multi-storied" stage. In westside forests, stands dominated by large trees, usually have giant trees scattered in the stand, with lower numbers in eastside forests. Grass/Forb or shrub understory often present, especially in canopy gaps. There is >70% total canopy cover, at least 10% or more canopy cover from large trees with another 10% or more canopy cover from 1 or more smaller tree size classes. Tree size is 20"- 29" dbh, and there are two or more canopy strata.


26) Giant Tree - Multi-story
FOREST26.JPG (246373 bytes) These stands have an overstory of giant sized trees with one or more distinct canopy layers of smaller trees. Stands with <40% canopy cover are classified in the "large tree - multi-story - open", stage. There is > 40% canopy cover. Tree size is > 30" dbh, and there are two or more canopy strata.

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