NRMT 4330 Silv Midterm

key hardwood forests in Ontario

- maple, yellow birch, red oak

- beech, white ash, hemlock

- basswood

- black cherry

harvest wood volume

maple (73% of area, 75% of volume), yellow birch, hemlock, beech, oak, ash, basswood, others

plasticity

ability to adapt and cope with environmental changes such as the ability to respond to release

sugar maple silvics

habitat: wide range, even or uneven, pure or mixed stands

shade tolerance: very shade tolerant

establishment: reproduces easily on undisturbed forest floor

development: determined height growth

american beech silvics

habitat: often mixed stand, occasionally pure

shade tolerance: very shade tolerant

establishment: easily regenerates on understory

development: determined height growth

yellow birch

habitat: pure and even aged fire origin stands or mixed stands

shade tolerance: intermediate shade tolerant

establishment: scarification aids regen, wind dispersed small seeds

development: indetermined height growth

red oak

habitat: dry sites

shade tolerance: intermediate shade tolerant

establishment: fire and clearcut best seed bed, responds well to release from moderate suppression

development: determined height growth

basswood

habitat: fast potential growth rate among hardwood species

shade tolerance: seedlings intermediate, mature shade tolerant

establishment: prolific stump sprouter, even age coppice in stand after disturbance, can regenerate entirely vegetatively

development: indetermined height growth

white ash

habitat: considered soil improvement species because high calcium leaf litter

shade tolerance: intermediate shade tolerant, seedlings shade tolerant but tolerance decreases with age

establishment: good response to release, leaf out later than associated broadleaf species. strong apical dominance, low epicomical branching

development: determinate height growth

black cherry

habitat: low plasticity, poor response to release

shade tolerance: shade intolerant, cannot survive under closed canopy

establishment: good natural regeneration, large seeds dispersed by birds

development: determined height growth

assessing individual tree vigor potential

crown position

crown size, leaf area

crown quality

bark character

degree of competition

stand relationships, whole stand view

assessing individual tree quality potential

DBH, larger higher value

site region

cull factor

tree growth rate

cutting cycle

a 20 year cycle to remove basal area, where every cutting cycle removes about 20% basal area

stand stocking

amount of trees in an area related to management objectives. density, crown closure, basal area

key differences between hardwood and softwood forests

phenology: timing of recurring natural evens like budburst, leaf expansions, flowering. boreal forests don’t lose their leaves in the winter

diversity: conifer forests significantly less diverse

vegetative reproduction: most important difference, hardwoods like aspens can reproduce vegetatively through sprouts and suckers

growth and mortality

most critical processes determining the fate of juvenile trees during natural regeneration

competition

an interaction between individual plants that reduces fitness of one or both involved

exploitation

when plants compete by reducing the availability of shared, limiting resources such as light, water and nutrients

interference

when fitness is reduced by mechanisms which do not directly involve limiting shared resources (allelopathy)

4 effects of competition

mutualism, mutually deleterious interaction, asymmetric facilitation, asymmetric competition

competition theories

ruderal: high reproductive and growth rate on disturbed sites

stress tolerator: low reproductive and growth rate on undisturbed sites

competitor: low reproductive effort and high growth rate, productive sites

grime’s theory

assumes that competition intensity increases with site productivity and competition success is defined in the capacity to capture resources

CSR triangle theory

C: high productive/high competition habitats

S: high environmental stress habitats

R: high disturbance (ruderal, open disturbed) habitats

tilman’s theory

total competition intensity is unaffected by habitat productivity though the ratio of aboveground and belowground competition varies. competition success is the ability to draw and tolerate resources to a low level

major mixed forests in BC

red alder, bigleaf maple, doug fir, cedar

paper birch, doug fir, spruce

aspen, paper birch, spruce

65.5% mixedwood in BC

why mixedwood

ecological sustainability: biodiversity, forest health - root rot, insect outbreaks, long term site productivity

multiple values and economic consideration

regulation - forest practice codes

spey creek project thinning

increased understory light

foliar responses

physiological responses

crown architecture

Ht, DBH and volume growth

raft creek project conclusions

thinning overstory birch to 600 spha provides enough light 60% for understory conifers

this density significantly reduced understory vegetation and birch sprouting

birch population research conclusions

birch populations from arid habitats tend to be less productive than populations from less restricted environments

paper birch population studies are better adapted to drought than low soil N

photo induction

there is lag time before a leaf reaches its Amax when exposed to high light after being in low light for a long time

other conclusions

shading to 60% of full light did not significantly reduce growth of all species studied

birch was more productive in mixture

silvicultural policies must be driven less by mill requirements and more by ecosystem dynamics

sugar maple development

determined

sugar maple moisture regime

fresh fertile well drained upland sites

american beech shade tolerance

very shade tolerant

american beech development

determined

american beech moisture regime

moist, fertile well drained fresh soils

yellow birch shade tolerance

intermediate

yellow birch development

indetermined

yellow birch moisture regime

moist, lower slopes, tolerant to poor drainage

red oak shade tolerance

intermediate

red oak development

determined

red oak moisture regime

dry sites, fresh to moist, well drained

basswood shade tolerance

seedlings intermediate, mature shade tolerant

basswood development

indetermined

basswood moisture regime

fresh to wet, moderately rich ecosites

white ash shade tolerance

intermediate

white ash development

determined

white ash moisture regime

very fertile, fresh to moist, well drained sites

black cherry shade tolerance

intolerant

black cherry development

determined

black cherry moisture regime

cool, moist, well drained sites

key differences between hardwood and softwood forests

phenology, diversity, vegetative reproduction

shade tolerance

the ability of trees to survive and maximize carbon gain in understory environments and ability to regenerate

ruderal competition theory

high reproductive and growth rate on disturbed sites

stress tolerator competition theory

low reproductive and growth rate on undisturbed sites

competitor competition theory

low reproductive effort and high growth rate, productive sites