Lesson 2: Disease Caused By Abiotic Agents Flashcards
Describe the general patterns of injury produced by abiotic injuries.
Abiotic injuries are often uniform, and affect a wider area. Biotic agents are less predictable and seemingly random.
How do extreme temperatures affect the health of trees?
High temperatures cause injuries where radiation loads are the highest. an example of these injuries are: sun scalding, pole blight, sugar exudation, and heat defoliation.
Low Temperature damages are:
Frost Damage: drought from frozen soil moisture, or mechanical freeze damage Ice forming in intracellular space that can cause membrane to rupture
Describe how nutritional disorders influence trees.
Nutritional issues affect a tree’s response to a pathogen or limit it’s growth and development. for example Nitrogen loading creates susceptible tissue to damping off fungi and frost damage
What Nutrient Deficinceis are most likely to occur in forest trees?
Nitrogen defienceis are most likely to occur, especially in younger soils found in PNW, as these soils are naturally low in nitrogen.
What are the three main types of air pollutants affecting forests and what are their sources?
Gasses, particulates, and acid precipitation.
they are typically emmitted in automobile exhausts, industrial plants , tanker spills, or agricultural acivities.
SO2 is the most common which comes from coal combustion and petroleum refining, ore smelting, and volcanoes
What damage does sulfer dioxide and ozone do to plans
Sulfur dioxide causes necrosis and chlorosis of broadleaved trees and tip necrosis of conifers. conifers shed needles prematurely, high concentration s cause death.
Ozone cause board leave plant flecking or stippling of upper surface.
bifacial necrosis, leaf reddening, and premature defoliation.
How does acid precipitation affect forest ecosystems
acid precipitation decreases the soil PH and nutrient availability, increasing soil Aluminum which kills fine roots and mycorrhizas.
How does nitrogen deposition influence forest ecosystems?
excess nitrogen deposition causes adverse impacts by inhibiting MG uptake, which is another important nutrient
Describe a situation where an abiotic agent’s damage on trees can predispose it to attack by a biological or biotic agent.
Frost cracking, which is a type of cold temperature damage, exposes wood and makes trees susceptible to spores of wood decay fungi.
Describe how you tell that trees were injured by deer, bears, or porcupines.
Animal damage is distinctive with clear symptoms.
Deer and elk predictably feed on seedling leaders in plantations.
Bears girdle trees by stripping bark from trunks.
Porcupines feed on sapwood and bark from the ground upwards which causes considerable decay.
