FEM Flashcards
(127 cards)
what is a disturbance
a sudden event in that time that removes biomass, disrupts ecosystem- community- or population structures and causes a rapid release or reallocation of environmental resources such as light, water or soil nutrients.
key aspects of disturbance
size, frequency and intensity
what should forest managers attempt? (in context of disturbances)
minimizing deleterious changes while maintaining future stand productivity and management options
what does harvesting intensity influence?
stand basal area, and in turn canopy cover and thus light availability
what are the two harvesting systems?
monocyclic (clearcut, all standing timber cut at once) and polycyclic (limited proportion of stems is cut)
what does monocyclic regenration depend on?
seed bank
what does polycyclic regenration depend on?
advanced regeneration, also called seedling bank
what is difference in canopy gaps between harvested and natural forest?
natural: small and quickly filled by advanced regeneration.
harvested: bigger and higher density. domineered by pioneer vegetation
what trees are found in logging roads?
pioneer species
consequences of too big canopy gaps?
soils drying out, nutrient loss through run-off, and herbaceous vegetation interfering with regeneration. And lots of regrowth may attract deer or other animals which damage regrowth and maintain open areas.
transformative change
not continuing business as usual, and radically changing our ways
forest-transition curve
forests are first lost for agriculture and then abandoned so the forest returns
how to achieve transformative change according to IPBES (international panel for biodiversity and ecosystem services)
formulate policies with the highest leverage (impact for action). Including reducing consumption, investing in technological solutions, shifting focus from economic welfare to human welfare
what is the role of soil in biogeochemical cycling
regulate fluxes of carbon, water and nutrients, and belowground storage
Mor soil
poor and infertile. Only an ectorganic layer (i.e., litter on top of the mineral soil).
Moder soil
intermediate fertility. Ah horizon (Layer where the mineral soil is mixed with humus), with darker humus incorporated in the mineral
layer.
Mull soil
rich and fertile soil. A deep Ah horizon (Layer where the mineral soil is mixed with humus) well, mixed, with a lot of bioturbation
how do above-below ground linkages differ
between fast (fertile soils) and slow (poor soils)
fast species (fertile soil)
thin, productive leaves with high nutrient value.
support high herbivore density. leaf litter layer high in nutrients and low in defense, bacteria and earthworm based decomposition. low net carbon accumulation and fast leaky nutrient cycling
slow species (poor soils)
long leaf life span, high defense, fungi and arthropod based decomposition, slow nutrient cycling and high carbon storage
3 drivers of decomposition:
litter (quantity and quality),
environment (conditions that speed up decomposer metabolism and activity)
decomposers (bacteria/macrofauna or fungi/microarthropods and what they can decompose).
Definition of decomposition
process where dead organic material is broken down into simpler organic or inorganic substances, such as carbon dioxide, water, simple sugars and minerals.
where is leaf litter production highest?
tropics, lowest in poles
where is leaf litter on forest floor highest?
poles, lowest in tropics