Wooded Uplands Key

This is a dichotomous key to wooded upland natural communities

Dichotomous keys work by making one of two choices. Start at number 1, and determine which of the descriptions best suits what you are looking at. Then click on the link under the "go to" column to take you to the next choice, and ultimately to the natural community description.

Number Description Go To
1 Conifer forests and woodlands: broad-leaved trees <25% cover 2
1 Broad-leaved or mixed forests and woodlands: broad-leaved trees >25% cover 24
2 Conifer forests: tree cover usually >65%, lower layers generally more sparse than canopy (except for dense patches of tree regeneration in canopy openings); area lacks a well-developed low shrub layer of lowbush blueberry, velvet-leaf blueberry, black huckleberry, sheep laurel, or black chokeberry ; substrate various, but often mineral soil, usually not a thin organic layer over bedrock 3
2 Conifer woodlands: tree cover usually <65%, as low as 20% (occasionally to ~80%), trees more-or-less open grown; low shrub layer of lowbush blueberry, huckleberry, sheep laurel, and/or chokeberry prominent (>15% cover), or sometimes bracken fern prominent (>10% cover) instead; ground cover may feature fruticose lichens; substrate bedrock, with a thin layer of mostly organic soil typically <15 cm deep 14
Conifer Forests    
3 Hemlock and/or pines dominant (near the coast, northern white cedar occasionally co-dominant) 4
3 Spruce and/or fir dominant 8
4 Hemlock dominant; red spruce, white pine, and/or cedar often present, sometimes co-dominant; stands may be either coniferous or mixed, strongly coniferous stands with very sparse herb and bryoid layers Hemlock Forest
4 Hemlock not dominant 5
5 Northern white cedar dominant; rocky hillslopes White Cedar Woodland
5 Pines dominant 6
6 Jack pine dominant, or co-dominant with black spruce; known only from western Maine Jack Pine Forest
6 Red pine or white pine dominant; more widespread 7
7 White pine dominant (highest basal area); red spruce, hemlock, and/or northern white cedar often present and may be nearly co-dominant White Pine - Mixed Conifer Forest
7 Red pine dominant (highest basal area); red spruce, white pine, (or coastally, northern white cedar) often present, may be nearly co-dominant Red Pine - White Pine Forest
8 Balsam fir dominant, heart-leaved paper birch and/or mountain ash often common, subalpine or coastal 9
8 Red and/or black spruce dominant 10
9 Coastal; white spruce often present Maritime Spruce - Fir Forest
9 Montane; white spruce absent Fir - Heart-leaved Birch Subalpine Forest
10 Variable canopy closure; black spruce or red-black hybrids often present; red pine occasionally present; heath shrubs prominent in herb layer (often >25% cover, may be very dense); usually on level, well-drained to xeric glacial deposits, sometimes with patches of saturated-soil and peat moss pockets in hummocky topography Spruce - Heath Barren
10 More or less closed canopy with mixtures of red spruce, black spruce, or other conifers; heath shrubs and herbs sparse (less than 20% cover), or if more, then with northern wood-sorrel, bluebead lily, tree regeneration may be dense in gaps 11
11 Red spruce, black spruce, or hybrids on level, poorly drained soils; wetland plants and peat mosses may be frequent, bryoids abundant (>50% cover) Spruce - Fir - Cinnamon Fern - Forest
11 Upland sites on till, bedrock, or talus, with red spruce or white spruce dominant; yellow birch and balsam fir may be occasional; wetland plants absent except in small seeps and ravines 12
12 Yellow birch often present and may form >25% cover. Herb layer with moderate to extensive cover of herbaceous species (often in patches), including northern wood-sorrel, bluebead lily, rose twisted-stalk, or mountain wood-fern; bryoid layer >20%, with feather-mosses prominent; northern/montane areas Spruce - Fir - Wood-sorrel - Feather-moss Forest
12 Yellow birch, if present, forms <25% cover. Herbs and dwarf shrubs sparse (<10% cover each); herb layer may include dense regeneration patches 13
13 Coastal (within mi. of the coast); white spruce often present, especially near coastline; bryoid layer >15% cover and not dominated by broom-mosses Maritime Spruce - Fir Forest
13 Widespread inland, may be near-coastal; both herb and bryoid layers very sparse; what bryoids are present include a large proportion of broom-mosses and pincushion moss Spruce - Fir - Broom-moss Forest
Conifer woodlands    
14 Northern white cedar the dominant tree species, usually twice as abundant as any other tree species White Cedar Woodland
14 Other species dominate tree layer 15
15 On talus, spruce dominant Spruce Talus Woodland
15 On bedrock (or, less commonly, sand or glacial till), various dominants 16
16 Mixture of conifer species, each <50% cover; or woodlands dominated by white pine or red pine 17
16 Pitch pine, jack pine, or spruce each ≥60% cover 18
17 Canopy dominated by red spruce or white pine (>60% cover), or by a mixture of conifers with none dominant, red spruce usually present Red Spruce - Mixed Conifer Woodland
17 Red pine dominant in canopy Red Pine Woodland
18 Jack pine dominates canopy Jack Pine Woodland
18 Other conifers dominate canopy; jack pine usually absent altogether 19
19 Black spruce the most abundant canopy tree 20
19 Pitch pine the most abundant canopy tree 21
20 Woodlands on bedrock, often coastal or on upper summits inland Black Spruce Woodland
20 Woodlands or forests on level or gently sloping till, occasionally with a thick organic layer Spruce - Heath Barren
21 Open woodlands on ledge; trees often stunted Pitch Pine Woodland
21 Open woodlands or sometimes almost closed forest, on sandy soil 22
22 Dunes or backdune areas along the immediate coast; bayberry almost always present Pitch Pine Dune Woodland
22 On glacial deposits, not dunes; inland or at least not at the immediate shoreline 23
23 Scrub oak extensive and locally dominant, making foot-travel difficult Pitch Pine - Scrub Oak Barren
23 Scrub oak absent or sparse, foot-travel easier Pitch Pine - Heath Barren
Broad-leaved or mixed forests and woodlands    
24 Forest seasonally saturated and/or discharging groundwater for significant periods during the growing season 25
24 Forest not seasonally saturated or discharging groundwater 28
25 Forest on gentle to moderate slope or flat bench within upland setting; discharging groundwater for significant periods during the growing season; dominant trees include ashes, sugar maple, red maple, yellow birch, or hemlock; jewel-weed often present Hardwood Seepage Forest
25 Forest may be saturated and flooded in the spring and adjacent to larger streams and rivers in a floodplain setting, or may be a somewhat elevated riverside terrace; ferns frequent 26
26 Floodplain forests with silver maple dominant and conifers absent or very sparse; usually along medium to large rivers. Herb layer includes ostrich fern and other ferns Silver Maple Floodplain Forest
26 Other hardwoods dominant (not silver maple) 27
27 High floodplain or terrace forests along medium to larger rivers in southern and central Maine, most often with sugar maple or red oak dominant, sometimes with yellow birch or ash dominant; on larger rivers this type is often found adjacent to but at slightly higher elevation than silver maple floodplain forests Hardwood River Terrace Forest
27 Floodplain with balsam poplar dominant or co-dominant with American elm and ash; northern Maine Balsam Poplar Floodplain Forest
28 Open broad-leaved woodlands (tree cover <65%) with birches, red oak, red maple, or ironwood dominant (Ironwood - Oak - Ash Woodlands may occasionally have a forest canopy >65% but they will key here: check description in couplet 31 below) 29
28 Broad-leaved or mixed closed-canopy forests (tree cover >65%) or mixed woodlands 32
29 Hillside or low summit woodlands dominated by red oak, without much ironwood or sugar maple, and with a heath shrub and bracken fern understory Oak - Pine Woodland
29 Not as above 30
30 Open to closed canopy woodlands on glacial till or outwash; early successional deciduous trees dominant (aspen, white/gray birches, red maple), red oak <40% cover (rarely up to 50%), conifers <30% cover Aspen - Birch Woodland/Forest Complex
30 Open woodlands on talus or thin-soiled hilltops rather than till or outwash 31
31 Woodlands on talus or thin-soiled hilltops and upper slopes; ironwood and oaks dominant (the former as either canopy or subcanopy), sugar maple occasionally common, and basswood often present but not abundant; with enriched site indicators e.g. round-leaved dogwood, herb Robert, hepatica, columbine, blue-stem goldenrod, and wide-leaved sedge Ironwood - Oak - Ash Woodland
31 Woodlands on talus; birches the most abundant tree; oaks and ironwood may be present but less abundant; enriched site indicators absent or very incidental Birch - Oak Talus Woodland
32 Broad-leaved component dominated by northern hardwood species (beech, yellow birch, sugar maple, red maple); red oak <30% cover 33
32 Broad-leaved component dominated by oak, white or gray birch, red maple, shagbark hickory, and/or aspen, rather than northern hardwood species 39
33 Mixed forests with conifers >25% cover 34
33 Deciduous forests, conifers <25% cover 37
34 Red spruce the dominant conifer Spruce - Northern Hardwoods Forest
34 Hemlock or white pine the dominant conifer 35
35 Hemlock the dominant conifer Hemlock Forest
35 White pine the dominant conifer 36
36 One or more northern hardwood species (beech, yellow birch, sugar maple) mixed with red oak and conifers; northern hardwood cover >15% Red Oak - Northern Hardwoods - White Pine Forest
36 Canopy almost entirely red oak and white pine (occasionally red spruce), sometimes mixed with red maple; northern hardwoods sparse Oak - Pine Forest
37 Some combination of beech, sugar maple, red maple, and yellow birch dominates the canopy, with sugar maple always <50% cover; ash and basswood absent or very minor; herb layer rarely >40% cover except for tree seedlings; enriched site herbs absent Beech - Birch - Maple Forest
37 Sugar maple dominant or co-dominant (≥50% cover); in southern or central Maine, white ash and/or basswood are usually present; herbs >40% cover 38
38 Several moderate rich site indicators are present, including doll's eyes, jack in the pulpit, grape fern, alternate-leaved dogwood, spikenard, and false Solomon's seal Semi-rich Northern Hardwood Forest
38 In addition to the species noted above, numerous uncommon rich site herbs such as leatherwood, Dutchman's breeches, maidenhair fern, and blue cohosh, and flat sedge are frequent. Sites are typically small acreages in sheltered sites (coves) or where calcium-enriched soils have accumulate Maple - Basswood - Ash Forest
39 Early successional deciduous trees dominant (aspen, white/gray birches, red maple), red oak <40% cover (rarely up to 50%), canopy closure variable from very open to almost closed; conifers <30% cover Aspen - Birch Woodland/Forest Complex
39 Oaks >50% cover, or if less, then canopy cover >35% coniferous 40
40 White oak, chestnut oak, and/or hickories present; southern Maine 41
40 White oak, chestnut oak, hickories absent or virtually so; statewide 43
41 Chestnut oak dominant or at least common; open-canopy woodlands (<65% canopy) Chestnut Oak Woodland
41 Other oaks dominant 42
42 White oak and red oak dominate canopy; hickory essentially absent White Oak - Red Oak Forest
42 White oak and red oak present and may be dominant, but shagbark hickory (and sometimes bitternut hickory) also present Oak - Hickory Forest
43 Closed-canopy forests with northern hardwood species (usually beech or sugar maple) >20% cover, may be co-dominant with red oak Red Oak - Northern Hardwoods - White Pine Forest
43 Beech, sugar maple, and white ash <10% cover each 44
44 Woodland structure: open canopy (<60% closure, occasionally more), trees well-spaced and often stunted; well-developed herb layer (>15% cover of dwarf shrubs and >5% cover of herbs), with graminoids often abundant and typical closed-forest species essentially absent Oak - Pine Woodland
44 Forest structure: canopy closure >70% and understory somewhat sparse, with dwarf shrubs much less than 15% cover; herbs include typical forest species such as Indian cucumber-root and wild-oats Oak - Pine Forest


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