FNRS 310 Exam 2

yield

amount available at any point in time

growth

change in characteristics over time

stand initiation

after a stand destroying disturbances, a new stand begins

stem exclusion

canopy classes winners + losers (mort) appear due to competition

understory reinitiation

overstory loses its grip on the understory; advanced regeneration appears

old growth

initial cohort is gradually replaced by many (3+) younger cohorts

shorten SI stage

planting, wedding, herbicide

shorten SE stage

thinning

mean annual increment (MAI)

current (cumulative) stand yield divided by stand age

what can MAI tell us

how long bio rotations, how much to harvest

periodic annual increment (PAI)

average growth over a series of years

density

refers to #, size, + disturb of trees

stocking

refers to # of trees, basal area, volume compared to what is considered optimum to max tree/stand growth

>A-line

too many trees occupy the site; total growth is slowed; many trees are suppressed - overstocked

<b-line

tree growth is good but not all growing space is occupied - understocked

btw A-B lines

trees occupy all the growing space but still have room to grow - fully stocked

what stocking charts tell us

space utilized, crowded, need reduced, need underplanted

stand density

degree of crowding/competition

stand stocking

ratio of crowding compared to what you could expect in optimum conditions

intermediate treatment

part of tending the stand in any silvicultural system; after successful regeneration + before final harvest

temporary

reduction in stand density to max growth + value of residual trees left for whole rotation

why we thin

site resources, influence species comp, improve tree quality, more income, shorten rotation, increase food

drawbacks of thinning

reduces gross production, creates potential damage, complicates forest mng

low thinning

thinning from below, german, favors dom + codom, imitates nat stand, best for markets for smaller trees, often used when moisture is limited

crown/high thinning

thinning from above, french, removes comp to favor best D-CD crop trees, OTs + INTs ignored, good for intolerant spp., higher $ returns

selection thinning

thinning of dominants, remove some Ds to favor growth of OTs, INTs, CDs, best applied in shade tolerant conifer stands, best applied early in stand

mechanical

geometric thinning, cut based on predeterminable spacing/pattern, mostly in young stands, may lead to lopsided crowns, very easy + cheap

grade A

remove over topped (OTs) trees

grade B

remove over topped trees, remove intermediate (INTs) trees

grade C

remove OTs, remove INTs, remove some “weak” codoms (CDs) , good for hardwoods

free thinning

combines elements of 2+ thinning methods to release most desirable crop trees

effect of thinning on residual trees

increased crown size, increased diameter growth, reduced self pruning of lower branches, increased taper, doesn’t increase tree height

weeding

removal of undesirable herbs + shrubs for stands in seedling stage

cleaning

removal of undesirable saplings for stands in seedling stage

liberation

for stands where the younger cohort not past the sapling stage is overtopped by much older trees

wolf tree

tree larger + older than those in a younger cohort