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RNR Study Guide Exam 2 Forests Forest Controversies Forest Values Open and Closed forests Hardwoods and Softwoods • Hardwood: a species of tree, such as oak, hickory, and maple that has relatively hard wood, in contrast to the soft woods of the conifers such as spruce and pine. DECIDUOUS • Softwood: a species of tree such as spruce, pine, and fir that has softer wood than hardwood trees such as oak and hickory. CONIFERS Stand Forest Succession Climax Community • The stable terminal stage of an ecological succession. Secondary Forests Old-Growth Forests Snags Factors that determine tree survival and distribution Shade-tolerant and shade-intolerant species Seed dispersal and germination
Pattern and rate of growth Tolerance of soil type Size/age at maturity Resistance to fire—surface fires and crown fires Surface Fires: “cool”, low level fire • Burns undergrowth and litter • Removes competing plants which is positive for the tree • Releases nutrients into the soil • Kill Fungi, which are bad for the tree • Improves wildlife forage • Prescribed burning is an important forest management too—makes forest much more healthy Crown Fires: extremely destructive • Burn entire forests • More common in fire—suppressed areas • Litter accumulation • Forest, wildlife, erosion impacts Fire = Negative Impact? • Used to be considered negative. After research fire is considered to be a key role in forest ecology. -Thick, Fire-resistant bark -Rapid regeneration after fire -Some trees include fire in their life history—need fire to reproduce -Fire climax trees: Giant sequoia, Longleaf pine—need fire to reproduce Diseases and parasites • Parasite fungi = most destructive • Viruses, Bacteria, Nematodes, Mistletoe • Most destructive on tree farms
• Exotics problematic (chestnut blight, Dutch Elm) Insects • Bark Beetles of pine and fir trees • Wood borers • Larval insects: defoliators—eating the leaves • Sucking insects, like aphids Pollution, SPMS, Ozone • Industrial urban areas in MDCs • Acid rain, ozone, and SPM: dust, soot, asbestos, heavy metals • Leaf and bark damage, increased susceptibility to pathogens World Forest • Forest cover 34% of world’s terrestrial biomes • Forestland decreasing in approx. 55% of countries, increasing about 32% • 0.22% loss of forest area/year during 1990’s • Deciduous needleleaf- baldcypress= lowest • Deciduous broadleaf= 2 nd lowest • Evergreen needleleaf= 3 rd lowest • Evergreen broadleaf= highest Firewood shortages • 50% of annual harvest is used for heating and cooking • By 2000, 3 billion people in 77 LDCs with firewood shortages • Burden on poor and women(bc women go out and get wood) • Burn manure and crop waste • Economic impacts of fuel changes—wood burning stoves =economic loss • Fuel wood consumption: South America and North Africa increase- they could switch to charcoal Increasing World Forest Yields • LDCs must plant more trees • Increase efficiency, switch to other fuels
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