Woody Vegetation of North American Biomes

Transcription

1 Woody Vegetation of North American Biomes 1

2 Biomes: the world s major communities includes plants, animals and abiotic factors generally defined by vegetation formations 2

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6 Net primary production (NPP) 6

7 Biome characteristics Climate: precipitation and temperature Plants: adaptations and species composition Disturbance: natural or human 7

8 Frequency: how often Disturbance Intensity: how severe and widespread Frequency and intensity inversely correlated 8

9 Fire Surface fires: Less intense and frequent-- many plants survive Typical of dry areas Crown fires: Intense and infrequent-- most plants die Typical of wet areas 9

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11 Other disturbances Human: agriculture, development, logging, mining, pollution, recreation Wind: regular wind, tornados, hurricanes Floods Pests: fungi, beetle, moth, deer 11

12 Ecological succession Change in community structure that occurs over time In forests, the trend is... shade intolerant to shade tolerant fast to slow growing less dense to more dense wood 12

13 Forest biomes Coniferous: landscape characterized by conical shapes Deciduous: landscape characterized by rounded shapes 13

14 Coniferous forests Boreal (taiga) Montane NW coastal / temperate rain forest 14

15 Adaptations in coniferous forest biomes Trees generally evergreen conifers Waxy cuticle Frost hardening Sunken stomates Shallow roots with mycorrhizae 15

16 Boreal / Taiga 16

17 World s largest biome Boreal forest climate Low temps, low precipitation, short growing season Treeline is northern boundary Many lakes and bogs Acidic and fairly wet soils 17

18 What is treeline? Area where trees stop growing happens abruptly Boundary with arctic (and alpine) zones Dwarf shrubs Krummholz growth Krummholz growth 18

19 Boreal forest 19

20 Plant species of boreal forest Second lowest species diversity Spruce (White, Black & Red), Fir (Balsam), Ericaceae, and Sphagnum Moss most characteristic. Pines and Larch/Tamarack also common. Four plant layers: trees, shrubs, herbs, surface 20

21 Spruce and Firs (short trees) Ericaceae (shrubs): Blueberries, Heaths Moss: Sphagnum 21

22 Pinaceae Larch / Tamarack, Larix spp. Jack Pine, Pinus banksiana 22

23 Crown fires Disturbance in boreal forest Timber harvest (pulp for paper products) Tar sands (oil) extraction 23

24 Coniferous forests Boreal (taiga) Montane NW coastal / temperate rain forest 24

25 Rocky Mountains Montane forest Sierra Nevada & Cascade Mountains Appalachian (sometimes considered boreal) 25

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27 Climate of montane forest Precipitation low (foothills) or high (subalpine) Snow most common precipitation (snowpack) 27

28 Alpine Subalpine Coniferous Deciduous Foothills Montane Zone 28

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30 Plant species of montane forest High conifer diversity Fir, Spruce, Hemlock, Lodgepole Pine, and Douglas Fir are common species Giant Sequoia, Bristlecone Pine unique to Sierras - World s most massive trees (dbh up to 37 feet!) - Word s oldest non-clonal trees (>5,000 years) 30

31 Fir (Abies spp.) Hemlock (Tsuga spp.) Spruce (Picea spp.) 31

32 Douglas Fir (Pseudotsuga menziesii) Lodgepole Pine (Pinus contorta) White Pine--5 needled (Pinus spp.) 32

33 Ponderosa / Yellow Pine (Pinus ponderosa) found at lower altitudes in the north than the south shade intolerant normally bad at regeneration (except in Black Hills and western Sierras) can be climax or seral species xeric vs. mesic forests frequent historic fires (5-20 year intervals favored Ponderosa) 33

34 Giant Sequoia (Sequoiadendron giganteum) Bristlecone Pine (Pinus longaeva, 2 others) 34

35 Giant Sequoia 35

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37 Prometheus & Donald Rusk Currey 2880 BC AD Radio Lab podcast: Be careful what you plan for 37

38 Disturbance in montane forest Fire naturally common; suppression has changed fire intensities Pests - Beetles - White Pine Blister Rust (Ribes and 5-needled pines, secondary host) Logging, livestock grazing, mining, recreation, pollution - Douglas Fir #1 timber species - Ponderosa Pine #3 timber species 38

39 Coastal Forest 39

40 NW coastal / temperate rainforest Mild temps, high precipitation (per year) Low precipitation in summer, especially in south (but lots of fog...) = winter wet, summer dry Rain shadow effect Why do conifers dominate in this mild climate? 40

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42 NW coastal/temperate rainforest 42

43 Plants of NW coastal/temperate rainforest High conifer diversity: - Cupressaceae: Coastal Redwood, False Cedars - Pinaceae: Douglas Fir, Spruce, Hemlock Coastal Redwoods: world s tallest trees Five plant layers: canopy, subcanopy, shrubs, herbs, surface 43

44 Coastal Redwood (Sequoia sempervirens) 44

45 Cedar / False Cypress, Chamaecyparis sp. Incense Cedar, Calocedrus sp. Redcedar / Arborvitae, Thuja sp. 45

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47 Disturbance in NW coastal/temperate rainforest Surface fires historically common Crown fires now sometimes occur Major center of logging worldwide Recreation 47

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49 Julia Butterfly & Luna: Northern Spotted Owl 49

50 Deciduous forests Northern mixed Central pure Southern mixed 50

51 Climate of deciduous forests Near absence of drought Moisture decreases east to west, south to north Moderate to long growing season Striking seasonal changes Strong microclimate variation 51

52 Plant species in deciduous forests Mostly angiosperms (few conifers) Relatively high overall tree diversity Five plant layers: canopy, subcanopy, shrub, herb, surface 52

53 Plant adaptation in deciduous forests Winter dormancy and deciduous habit Frost hardening Spring ephemerals: perennial herbs Broad leaves 53

54 Figure 1. The nine regions described by Braun (1950), representing original forests of eastern North America. James M. Dyer BioScience 2006;;56:

55 Northern mixed deciduous forest Hemlock-White Pinenorthern hardwoods association White Pine (conifer) was most widespread, late successional tree Quaking Aspen & Paper Birch early successional Logging and slash fires altered landscape 55

56 Central "pure" deciduous forest Deciduous = only major growth form Huge tree diversity! Common species = American Beech, Basswood, Sugar Maple, Oaks, Hickories, American Chestnut 56

57 Central "pure" deciduous forest Some familiar South Dakota trees here Ash (Green and White) Aspen (Quaking and Big Tooth) Box Elder Cherry (Choke and Black) Cottonwood (Plains/Eastern) Dogwoods Elm (American, Red, and Slippery) Hawthorns Hop Hornbeam Oak (Bur and many others) 57

58 Oak-Hickory-Chestnut Shagbark Hickory 58 American Chestnut

59 Beech-Maple-Basswood Maple Beech Healthy Infected Basswood 59

60 Other tree species American Sycamore Sweetgum Buckeye Magnolia Sassafrass Tuliptree 60

61 Central Pure forest species Aceraceae: Maple Family -Acer spp. Fagaceae: Oak Family - Quercus spp., Oaks - Castanea dentata, American Chestnut - Fagus grandifolia, American Beech Juglandaceae: Walnut Family - Carya spp., Hickories - Juglans nigra, Black Walnut Magnoliaceae: Magnolia Family - Liriodendron tulipifera, Tuliptree - Magnolia spp., Magnolias Tiliaceae: Basswood Family - Tilia spp., Basswoods 61

62 Southern mixed deciduous forest Both deciduous and coniferous growth forms Early successional trees = pines (many spp.) Late successional trees = oaks (many spp.) Spanish Moss and Live Oaks common 62

63 Live Oak with Spanish Moss 63

64 Variable natural fire regime Pests - Fungal: Dutch Elm disease, Chestnut blight, Beech bark disease, Oak wilt - Insect: Emerald Ash Borer (beetle), Gypsy Moth, Hemlock Wooly Adelgid (true bug) - Deer Disturbance in deciduous forests Agriculture, logging, mining, and development 64

65 Chaparral shrubland Mediterranean climate: cool wet winters and hot dry summers 65

66 Plant adaptations to chaparral Fire tolerance: - sprout from belowground buds - seeds only germinate after fire - flammable chemicals in finely divided leaves - plant adapted to catch fire Drought tolerance: - very deep or wide spreading roots - thick cuticle - vertical leaf orientation 66

67 Plant species in chaparral Adenostoma fasciculatum Chamise (Rosaceae) Scrub Oak Arctostaphylos spp. Manzanita (Ericaceae) 67

68 Disturbance in chaparral Historically, fires are occasional but periodic-- intense and burn most aboveground vegetation Fire intensity, frequency now increased due to fire suppression Grazing and urban development As bordering coniferous forests damaged, chaparral is increasing 68

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70 New World Tropic "neotropics" 70

71 Climate of the tropics Little seasonality: wet season & dry season (only) Long growing season (can be 365 days) Warm, high precipitation, high humidity Extremely nutrient-poor soils 71

72 Climate of the tropics 72

73 Plant species of the tropics Exceptionally high species diversity-- few dominant species Evergreen & deciduous angiosperms Six layers: protruding, canopy, subcanopy, shrub, herb, and surface Tree canopies very dense; most life in canopy (myth of the jungle ) NPP greatest of any biome 73

74 Adaptations in the tropics Defense to intensive herbivory Nutrient gathering in low-nutrient substrates Photosynthesis in low-light environments 74

75 Prop/stilt roots Buttresses Shallow roots... 75

76 Epiphytes Drip tips 76

77 Lianas 77

78 Evergreen angiosperms Spines and thorns 78

79 Disturbance in the tropics Treefalls and canopy gaps Slash & burn agriculture (1500's - recent) Modern agriculture, grazing, logging 79