Lecture 11

Question 1

demand of timber is

Answer 1

increasing

• wood fuel, charcoal, pellets, paper and paper board, sawn wood, industrial roundwood
• global demand increased by over 300 million m3 from 2012-2016

Question 2

ectomycorrhiza found in __ of plant species

Answer 2

in only 3%, but these plants are exceptionally important dominant around the globe

Question 3

the total C pool in forest ecosystems is about ___ Gt, out of a global ___Gt of which __% is boreal forests

Answer 3

1190Gt
2110 Gt
58% in boreal forests

Question 4

in boreal zone __% of C is in soil and plant litter

Answer 4

62%

Question 5

what is the worlds largest vegetation system

Answer 5

Boreal forests
-over 35% of the global forest cover is provided by ectomycorrhizal trees in boreal forests (Ecto useful in storing carbon)

Question 6

the ____ & __ are experiencing the greatest rates of warming and models suggest they will continue to do so

Answer 6

northern hemisphere boreal forest and tundra

Question 7

threats to the boreal forest

Answer 7

logging, fire, pine beetle (normally ok as cold winters kill them off), global warming

Question 8

burning of forests =

Answer 8

• common in north america, less fires but the first which do occur are much bigger
• British columbia, canned nearly 13,000 km2 burnt in 2018

Question 9

bad outcomes from forest fires

Answer 9

often generate extra lightning storms from the upwelling heat, smoke and water vapour (create their own microclimates)

• file tornadoes reported in 2018 Californian forest fires
• pollution from particulate carbon

Question 10

post fire soil erosion and degradation

Answer 10

• wash off of ash, and erosion
• takes a long time to recover, whole soil system gets reset 1000 of years
• soil loss and soil erosion a major problem often in areas where it is not normally
• BUT lots of charcoal, biochar may accumulate in soil and have beneficial effects (storing carbon)

Question 11

logging: carbon loss

Answer 11

a lot of carbon originally stored in forest floor, this takes a long time to recover after logging
-even after 79 years post logging, a lot of carbon bad but in trees not in ground so risk of burning and its gone

Question 12

ectomycorrhiza:

Answer 12

• 70-112 m2 hyphal absorptive area per m
• EM compromise 70% of the total soil microbial biomass
• from 2.5m2 of forest soil EM can wrap around the earth

Question 13

ectomycorrhizal fungi =

Answer 13

• almost exclusively in basidiomycetes, a few ascomycetes
• over 95% of root times of pine, spruce and fir trees ar covered in fungus (Taylor et al 2001)
• roots not in contact w soil
• almost all organic carbon passes through fungus

Question 14

ectomycorrhizal fungi produce a range of extracellular enzymes that are involved in

Answer 14

hydrolysis of organic C, N & P containing components of litter and C- containing structural components of plant litter

Question 15

Perez-Moreno & Read 2000 Leaf litter

Answer 15

-beech tree litter & birch sapling tree , positive feedback between nutrient uptake by EM mycelia and increased lead area for C fixation .

Question 16

EM uptake of N & P result in

Answer 16

left over high carbon , nutrient poor organic matter. other organisms cannot decay these
- increased C:N ratios

Question 17

EM & Tannins

Answer 17

partly depolymerise the tannins

Question 18

tree logging: cutting down Coastal Redwood

Answer 18

• live up to 3500 y
• stem biomass = 3500 tonnes /ha
• N content of 0.1% (3.5 tonnes per hectare)
• same amount of N you add to wheat field for ten years
• cutting down you lose the nutrients accumulated over 100 generations

Question 19

much tropical deforestation does not involves timber extraction but

Answer 19

burning

• for clearance for grazing land etc
• lose 7.7% per year

Question 20

most tropical trees are ___ mycorrhizal

Answer 20

arbuscular

Question 21

majority of tropical forest changes are for

Answer 21

food production (mainly animal feed) at the cost of biodiversity and ecosystem carbon storage and soil

Question 22

palm oil & forests

Answer 22

clear a lot of forest to grow it

• in a lot of products
• Tsujino et al 2015
• major source of vegetable oil

Question 23

trees agroforestry

Answer 23

• Zomer et al 2016
  (trees on agricultural land)
• sequest a lot of carbon
• globally these trees increasing by 2% each year
• soil organic carbon is higher when you have trees at edge of fields (Pardon et al 2017)

Question 24

soil water movement and hedgerows

Answer 24

water pulled out towards hedges (build up water capacity in soil)
- soil at the hedge can capture soil reducing risk of contaminated waters going into streams / rivers
-flood risk mitigation & pollution
Ghazavi et al 2011

Question 25

train track trees

Answer 25

trees nearby are chipped an left, could we not use it for efficiently? fuel?

Question 26

Draw power station largest in UK

Answer 26

to keep it burning for longer buning coal to –> burning wood pellets (which we import from the USA)
- marginally better, but where is it being cut down from?!

Question 27

californian biomass ‘waste’

Answer 27

estimated 14 million dry tons of forestry residue could be sustainably processed each year for energy

• could help reach bioenergy targets
• should think carefully on how we are using such materials

Question 28

sustainable forest ecosystems: issues to consider

Answer 28

1) climate change impacts and interactions
2) soil degradation on removal of forest cover
3) nutrients in wood ash quickly washed away
4) tree removal in high rainfall areas like the tropics causes extreme soil erosion and soil degradation
5) problems of nutrient export on logging
6) competition for fertilisers (NPK) between forest production and food production
7) competition for land biofuels /crops
8) biofuels temptation to use forestry waste but where is this coming from
9) increasing g demand for wood and paper
10) opportunities to make greater use of agro-forestry & tree legumes and tree food crops

Question 29

ectomycorrhiza vs arbuscular mycorrhiza

Answer 29

arbuscular = penetrate cell membrane for nutrient exchange, greater surface area

ectomycorrhiza = can break down complex organic substrates

Both transfer N & P to plants in exchange for C