L6 - Logging

Question 1

How much logging has occured in recent years?

Answer 1

• Between 2000-2005, 20% of tropical forests were logged
• Over 400 mill. hectares of tropical forests in permanent timber estate (area the size of the EU)
• Logged forests now dominate the remaining global tropical forest cover

Question 2

What method of logging is used in the tropics?

Answer 2

Selective Logging - only large, marketable trees are removed. Smaller individuals or undesirable species left

Question 3

What has been the consequence of selective logging in the tropics?

Answer 3

• Damaged forest remains
• Damage depends on how much wood is cut
• Logging has lowered the canopy structure by removing the tallest trees and leaving the smaller ones

Question 4

What concessions have been made to manage tropical tree damage?

Answer 4

• Only cut trees above a set diameter at breast height (DBH) = 50-60 cm
• Harvest in rotations, typically 40-70 years apart

Question 5

How have these concessions been broken?

Answer 5

• early re-entry into logging sections
• reduced tree size (eg. 60 –> 40 cm DBH)
• fishing down the value chain
• Reopen and create more logging roads
• Further damages forest and reduced future timber yields

Question 6

What does ‘Ecosystem Functioning’ mean?

Answer 6

The biological, geochemical, and physical processes that operate within an ecosystem, sustaining it and enabling it to supply ecosystem services

Question 7

Give some examples of Ecosystem Functions

Answer 7

• Nutrient cycling, seed dispersal, pollination
• Interactions within and between the structural components of ecosystems (eg. biodiversity, water, soil etc.)

Question 8

What is effect of Logging on biodiversity?

Answer 8

• Causes differences in the number of rarefied species richness
• The Orangutan does very well in areas with high selective logging (44% live in active or former logging concession, 22% live in protected area)
• This is because the younger trees in logged areas grow more fruits which the orangutans eat
• The Bornean Gibbon is becoming threatened

Question 9

What metrics are used to measure the consequences of consistent logging?

Answer 9

1) Species composition - what species are making up communities?
2) IUCN red-listed bird species - what species are vulnerable and endangered?
3) % of unlogged species persisting - what species cannot survive in logged forests

Question 10

What taxa did Edwards et al. study and how did they measure them?

Answer 10

Birds - point counts and mist nets (understory birds)

Dung Beetles - baited pitfall traps

Leaf-litter ants - winkler traps

Question 11

Why were these species chosen?

Answer 11

They all have key functional roles in the ecosystem - eg. seed dispersal, nutrient recycling and predation - and are easy to capture

Question 12

What is the difference in the number of red-listed bird species in unlogged vs logged forests?

Answer 12

There is a significant decline in the abundance of these birds from unlogged to logged, but the abundance doesn’t drop to zero - birds can still persist in logged forests

Question 13

What are the negative impacts of logging on Biodiveristy?

Answer 13

• Changes species composition
• Some species apparently extinct in landscape
• Logging is harmful, re-logging magnifies harm

Question 14

What are the positive effects of logging on Biodiversity?

Answer 14

• Substantial amount of biodiversity persists
• Includes red-listed species (eg. Orangutan)

Question 15

What are the problems caused by the conversion of logged forests to palm oil agricultural areas?

Answer 15

• Oil palm plantations are a monoculture
• no understory present at all
• dramatically reduced number of species in oil palm plantations than logged forests - 66% decrease
• around 10 IUCN red-listed species in point counts in logged forests, and almost 0 in oil palm plantations

Question 16

How have oil palm plantations affected birds?

Answer 16

• including granivorous spp
• loss of bark cleaners
• arrival of water-related spp

Question 17

How have oil palm plantations affected dung beetles?

Answer 17

• absence of rollers
• < diet generalist species
• > smaller species

Question 18

What are some impacts of logging on ecosystem services?

Answer 18

• The natural environment provides human society with many ‘services’
• Eg. forests store carbon → mitigate climate change
• Primary forests store billions of tons of carbon
• Carbon sinks for 3+ decades, absorbing more carbon than they emit

Question 19

What are the consequences of more roads being built in tropical forests (eg. Congo Basin)?

Answer 19

• Animals walk on the new roads
• Increased risk of being runover or trapped
• 64% increase in bushmeat consumption coincides with a 69% increase in populations of logging villages
• near roads there is a lower chance of finding an elephant so their territory is decreasing as number of roads increase

Question 20

How are fires disrupting tropical ecosystems?

Answer 20

• Canopy disruption and roads promote desiccation
• fine slash from logging highly flammable
• however, susceptibility to fire dimisnihes within a few years