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Threats to our forests

Threats to our forests. Abiotic / B iotic threats. Abiotic frost, hail, acid precipitation, fire Biotic Forest diseases – usually fungal infections of leaves / roots / bark Forest insects – usually larva of moths or beetles eating the leaves. Abiotic.

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Threats to our forests

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  1. Threats to our forests

  2. Abiotic/ Biotic threats • Abiotic • frost, hail, acid precipitation, fire • Biotic • Forest diseases – usually fungalinfections of leaves / roots / bark Forest insects – usually larva of moths or beetles eating the leaves

  3. Abiotic • Frost Damage – usually to young deciduous saplings in late spring

  4. Ice Storms / Hailstorms • Worst in Ontario history 1998

  5. Acid Precipitation • Leaches nutrients from leaves • Damages waxy coating (cuticle) on leaves – leaves dry up

  6. Forest Fires • About 8000 forest fires per year in Canada covering 2 million hectares • 45% started by lightning • $1 billion annually to fight forest fires • However, fires are part of the natural cycle of forests – some species rely on extreme heat for seed release from cones (e.g. Jack pine)

  7. Forest Diseases - examples • Dutch Elm Disease – caused by a fungus spread by a beetle • First introduced to N.A. in 1928 by way of imported lumber • Spread to Ontario in 1967 • In Toronto, 80% of the elm trees died

  8. White Pine Blister Rust • Invasive Species – a fungus that came into Ontario early 1900s on European tree species. • Affects white pine (a valuable timber tree) – tree eventually dies

  9. Root Rot / Leaf Spot

  10. Forest Insects 1. Tent Caterpillars • Population cycles, can defoliate many types of deciduous trees

  11. Eastern Tent Caterpillar Range

  12. 2. Mountain Pine Beetle • Lodgepole pine trees of British Columbia • Carry a fungi which blocks flow of water/nutrients in the tree • Within 2 weeks of infection, the trees starve to death • Warmer temperatures have increased their range!

  13. Blue-stain fungus blocks water flow and is what kills the tree.

  14. In 10 years, the pine beetle has destroyed half of B.C.’s lodgepole pines.

  15. How long before this arrives in Ontario’s boreal forest?

  16. 3. Gypsy Moth • Invasive species (native to Europe and North Africa) • Arrived in Southern Ontario 1970s • Defoliates mainly deciduous trees in Ontario / eastern U.S.

  17. Gypsy Moth Damage

  18. Control of Gypsy Moth • - egg mass scraping- caterpillar removal- pheromone traps (uses scents which draw the caterpillars in and kill them)

  19. 4. Emerald Ash Borer • Arrived in the Toronto area in the last decade • Trees cut down if infected • Public Education – don’t move firewood around the province

  20. 5. Spruce Budworm • Moth that is native to Canada • Larva are pests of fir and spruce dominated forests, especially mature forests. • Extensive damage to economically important timber forests

  21. Should we control for a native species (like Spruce Budworm)? • Largest forest insecticide spray program in Canada • DDT until 1968 when it was banned • Pesticides toxic to other species including birds that eat the larvae

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