Lecture 11 - sustainable forestry

Question 1

how much habitable land area is forest?

Answer 1

37%

Question 2

what forest types have high biomass e.g high amounts of carbon stored in trees?

Answer 2

tropical rainforests

Question 3

what is a global tree restoration potential?

Answer 3

• Because of the quantity of carbon stored in trees they could become part of the solution to get carbon back out of the atmosphere and back into biomass
• however there are lots of threats on tree stocks

Question 4

what threatens trees?

Answer 4

• wood products
• fuel e.g. Africa and Asia are big contributors - huge numbers of poor people that live around tropical forests etc and they are extremely reliant on wood as primary source for heating and cooking - also has issues for pollution e.g. smoke particles etc

Question 5

what is the problem with trying to reduce wood use for fuels?

Answer 5

• Question is how we help these poor people by providing alternative technologies which allow them to reduce the requirement to chop down trees

Question 6

describe carbon storage in boreal forests

Answer 6

• Stores a lot of carbon in both the forest and the soil - actually more than tropical forests however most in soil not trees

Question 7

what type of mycorrhiza are found in boreal trees?

Answer 7

• Ectomycorrhiza- found in only 3% of plant species, but these plants are exceptionally important dominant components of some forest ecosystems
• Ectomycorrhiza may be important assisting global soil C sequestration particularly in the boreal forest

Question 8

where are the highest carbon storage areas found?

Answer 8

peats -where Sphagnum mosses rather than trees are normally dominant

Question 9

describe the root systems of plants which have ectomycorrhiza

Answer 9

• HUGE AMOUNTS OF FUNGI ON THE ROOTS - therefore root systems tend to be smaller as they invest so much in the mycorrhizal hyphae

Question 10

Ectomycorrhiza: >95% of root tips of pine, spruce and fir trees are sheathed by fungus - what does this mean?

Answer 10

• These roots have no physical contact with soil
• Virtually all plant nutrient and water uptake is through fungus
• Almost all organic carbon released from living roots passes to the fungi
  PROVIDE CRITICAL INTERFACE BETWEEN TREE AND SOIL

Question 11

Difference between Arbuscular mycorrhiza and EM?

Answer 11

-The enzymes they maintain

Question 12

what do EM extracellular enzymes do?

Answer 12

• Ectomycorrhizal fungi produce a range of extracellular enzymes that are involved in the hydrolysis of organic C, N and P containing components of litter, and C- containing structural components of plant litter
• Actively involved in decomposing organic matter to a certain degree and releasing nutrients preferentially from that

Question 13

describe nitrogen cycling in EM

Answer 13

• EM is able to develop a short circuit where it takes up organic nitrogen bypassing other microorganisms and fauna
• Selective depletion of easily altered N by ectomycorrhiza restricts access to N by saprotrophs thereby inhibiting both N and C mineralisation- minimising N losses from these plant guilds
• Very efficient mycorrhiza

Question 14

why is the plant species diversity low in boreal regions?

Answer 14

because the trees can compete with herbaceous plants that don’t have the ability to tap into organic nitrogen stores so just rely on mineral nitrogen pools- high dominance by these trees

Question 15

what do ectomycorrhiza also allow trees to gain access too which most other plants cant do?

Answer 15

aluminium phosphate -

Question 16

how do EM trees deal with tannins?

Answer 16

adapted ways of coping with soils litters rich in tannins and ways they can recycle nutrients from within this - some EM actually produce enzymes that can partially degrade tannins

Question 17

what is a big threat to boreal forests?

Answer 17

• The northern hemisphere boreal forest and tundra are experiencing the greatest rates of warming and models suggest they will to continue to do so
• Big temp changes in boreal regions compared to global averages
• Potential threats to soil C stocks and increased risks of forest fires
• Burning is becoming quite a big issue in terms of loss from these regions

Question 18

7 common threats to boreal forests

Answer 18

1) Logging
2) Fire
3) Pine beetle - transmits infection to the trees - abundance is rising with temp increases
4) Climate change/global warming
5) Increasing co2 emissions from wildfires - a lot of these fires are cause by humans
6) Temperate forest losses are increasing
7) Forest fires often generate extra lightning storms from the upwelling heat, smoke and water vapour - one big fire can cause multiple fires in a cascade of effects

Question 19

2 consequences of fires 1= positive 1= negative

Answer 19

• Post fire soil erosion and degradation

- Can generate charcoal which could be stabilised in the soil and potentially contribute to long term carbon stocks

Question 20

why is replanting after logging not a quick solution?

Answer 20

• Even after replanting it takes nearly 80 years to recover biomass and carbon stocks in the soil back to the same point

Question 21

describe an additional problem of oil palm trees compared to other agricultural trees

Answer 21

• Oil palm is particularly damaging compared to other agricultural trees in terms of erosion

Question 22

what is agroforestry?

Answer 22

a way of sustaining food production and soil ecosystem services
- Range of different types of agroforestry systems e.g. field margin trees

Question 23

To try and meet climate change projections, how many trees do we need to plant?

Answer 23

1.5 billion

Question 24

describe how the UK is doing for meeting climate change projections in terms of trees?

Answer 24

• Tree planting has actually decreased in England

- Some of England power stations are actually run by wood not coal - we are actually importing this from north America