1
Q
How much of the Earth’s surface is covered by forests?
How so they link to the community? What conditions do they need?
A
30%
They are often the climax community and are found wherever conditions are suitable:
- soil presence
- climate that does not involve prolonged dry periods/serious fires
- temperature determines what kind
2
Q
Give some example percentages of country’s forest cover
A
Finland 72%
UK 11%
Brazil 62%
DRC 45%
Indonesia 52%
Russia 50%
3
Q
Why are forests typically the climax community?
A
they represent the final, stable, and self-perpetuating stage of ecological succession, characterized by:
- mature trees
- high biodiversity
- complex food webs
- a balanced mix of species well-adapted to the local climate and conditions
They reach equilibrium until a disturbance (like fire or logging) resets the process
4
Q
Give some different types of forest
A
- Taiga (boreal forest)
- Temperate deciduous forest
- Tropical rainforest
5
Q
Where is the Taiga?
A
- northern, cold latitudes, coniferous forests
6
Q
What are the abiotic conditions in the Taiga?
A
- low evaporation
- low precipitation: 50-150mm/year
- cold
- variable light seasonally (though low sunlight)
7
Q
What are the biotic conditions of the Taiga?
A
- low biodiversity
- evergreen forests = pts in low light levels
- low primary productivity as pts = slow, so low energy production for higher trophic levels
8
Q
Where are temperate deciduous forests?
A
mainly mid-Northern latitudes
9
Q
What are the abiotic factors in temperate deciduous forest?
A
- seasonal variations as in the UK
- moderate rainfall: 100-200mm/year
- reasonable light levels, undergrowth shaded
10
Q
What are the biotic factors like in temperate deciduous forest?
A
- deciduous to reduce evapotranspiration and snow damage in winter
- trees such as ash, oak, beech, maple, lower story shrubs
- higher primary productivity and biomass than Taiga
11
Q
Where are tropical rainforests located?
A
equatorial and southern equator
12
Q
What are the abiotic conditions in the tropical rainforest?
A
- high temp
- high rainfall: (250 ->400mm/year)
- frequent rainfall
13
Q
What are the biotic conditions in the tropical rainforest?
A
- primary productivity and bidiversity very high due to all-year-round growth
14
Q
What are the importance of forests?
A
- resources
- ecosystem services
15
Q
How are resources gained from forests?
A
- both HICs and LICs gain a wide range
- some extracted from existing forests, most produced by cultivated plantations of species that were discovered in forests to meet the growing demands of the human population
16
Q
What is the issue for resources as wild forests are lost?
A
we may lose valuable species that become extinct before their importance is understood, or even before they have been discovered
17
Q
What are some of the resources extracted from forests?
A
timber
fuel/firewood
food/animal food
medicines
fibres
OTHER:
- paper
- fruit
- gums
- resins
18
Q
How does the importance of forest resources differ between HICs and LICs
A
HICs
- paper used far more
- farming is more destructive monoculture, but there can be agroforestry
- fuelwood generally only used in home fires, not for domestic/commercial/industrial consumption/use
- eat less of the raw forest resources: we grow fruit and nuts commercially now, and have UPFs
- medicine access such as aspirin is much higher
LICs
- farming may be subsistence or traditional, though some areas may be destructively cleared for commercial plantations and monocultures for export to HICs
- fuel wood is more important for households and industries, such as cooking
- more likely to eat the raw resources like fruits and nuts, and be more gatherers
19
Q
Give examples of HIC paper usage
A
CHINA = 103m tonnes a year
USA = 71m tonnes a year
20
Q
How are forests vital to global ecosystem regulation? What is their role?
A
- contain twice as must carbon as is in the Earth’s atmosphere
- act as a vast water store, releasing water slowly through evapotransp
- slow down raindrops = reduced INFILTRATION, rain splash, erosion and overland flow
- BIODIVERSITY: tropical rainforest sustain 40% of all life on Earth
- they are typically ecologically stable and a source of valuable genes
21
Q
What is traditional forest management?
A
- managing existing woodland areas to maximise the forest yield
- rarely involved the total removal of the natural forest and often retains the original mix-species structure with trees of different ages
- often overlap between forest management and agriculture in symbiosis as a form of early integrated multi-culture (agroforestry)
- pre industrial societies used a wide variety of species, each having its own particular characteristics for different uses
22
Q
What are the characteristics of modern commercial forestry?
What are the problems with it?
A
- natural woodlands being replaced by plantations
PROBLEMS:
- generally unattractive
- non-native species attract little wildlife
- typically planted in straight lines that provide little variation in abiotic conditions
- simple age structure = few niches created, due to lack of biological diversity (i.e. few mature trees/saplings)
- all trees tend to be harvested at a similar time - meaning little or no deadwood is left, reducing levels of DOM in soils
23
Q
What is the goal of sustainable forest management?
A
- harvest maximum resources without compromising future harvests; harvesting at a rate it can regenerate - NOT ALL AT ONCE
- population sizes kept far below carrying capacity, enabling fast growth
- keeping MSY relevant, to prevent adverse or encourage positive interactions between species, and alter entire ecosystems
- determining target population size to keep all these species interactions natural and at a good level, but it is largely a matter of trial and error
- ensure healthy, productive forests for present and future use
24
Q
Using MSY as a concept, explain why deforestation could be described as unsustainable exploitation
A
- if we take too many trees, they can no longer provide adequate ecosystem services that support the entire community
- this would lead to their rapid population decline, without good breeding, and also the population decline of all the species that rely on them
- this could be a sudden collapse, as the species will first try to adapt to changing population dynamics, before they succumb to competition and loss of resources
25
What are the causes of deforestation/forest loss?
- agriculture
- mineral extraction
- reservoirs
- urbanisation
- transport infrastructure
26
What are the SIGNIFICANT causes of forest loss/deforestation, i.e. why are forests not naturally replenishing?
- harvesting is over the MSY e.g. for timber or fuelwood
- insufficient replanting
- clearance for agriculture, HEP, roads, urban development and mineral extraction
27
What are the effects of deforestation?
- loss of forest resources
- ecological impacts (like reduced biodiv)
- impact on soil
- changes to hydrology
- climate impacts
28
What are some of the countries that supply (and stats):
a) timber
b) fibres
c) fuelwood
d) food/animal food
e) medicines
a) Canada: 9% world's forests, 10% softwood lumber trade
Brazil = 19% mouldings industry exports, also valuable species like Ipê (Brazilian Walnut)
b) USA and Indonesia = wood pulp (e.g. for paper)
Sweden and Finland (Nordic countries) = wood based fibres e.g. Spinnova, Finland: Uses a patented mechanical process to spin wood pulp into high-performance, biodegradable fiber with zero harmful chemicals, partnering with brands like Adidas
c) ~50% all wood removals are for fuel
Asia and Africa: 75% all woodfuel removals
Ethiopia and DRC: wood charcoal (but the rainforest?!)
d) Indonesia and Malaysia: >85% world's palm oil
Côte d'Ivoire and Ghana: >50% world's cocoa
USA, Brazil and Argentina: soybeans and corn used in cattle feed etc
e) Amazon Rainforest supplies 25% of all drugs used in Western medicine
China is 24% of exports market, India is 12% - incl Turmeric, famous for anti-inflammatory and arthritis benefits
29
Describe the global distribution of forests
Give example countries for each
TAIGA (BOREAL): far north, just below the Arctic. Canada, Scandinavia, Russia
DECIDUOUS (TEMPERATE): above the Tropic of Cancer, below the Tropic of Capricorn, not too far North. Europe, UK, USA, E. China, E. Australia
TRF: on the Equator, between the Tropics. S. America, E. Africa, DRC, SE Asia, Indonesia
30
What ecosystem services do forests provide?
- atmospheric regulation
- regulation of the hydrological cycle
- forest microclimate
- habitat and wildlife refuge
- soil conservation
- recreation/amenity usage
31
How does C storage differ between types of forest and all other terrestrial ecosystems?
Consider statistics for TRF, temperate, and Taiga (boreal), and also whether it is soil or living veg store
(stats are in x10 -9 tonnes)
Total forest storage = 1160
All other terrestrial ecosystems = 1330 (1220 soils, 110 in living veg)
TRF = 430 (the middle) (220 in soils, 210 in veg)
Temperate = 160 (the least) 100 in soils, 60 in living veg)
Boreal = 570 ( the most) (480 in soils, 90 in living veg)
32
What 3 scales do forest ecosystem services influence?
Give an example
- local (Amazon rainforest climate/rainfall)
- national (Brazilian/South American rainfall/climate
- global (global O2 release, C sequestration and CC regulation)
33
What are the uses of different tree species in traditional forest management?
Give examplse
Wood from diff species has diff properties, therefore diff uses:
- oak = ship building
- beech = tool handles, furniture
- ash = roof timbers
- holly = mathematical instruments
- hazel = fencing panels
34
What are the traditional forestry management methods?
- standard trees
- coppicing
- pollarding
35
What is the "standard trees" traditional forestry management method?
Give uses
- desirable, tall, straight-timber trees that develop knot-free trunks
- trees that were grown to maturity for the production of large timbers
e.g. uses such as the construction of buildings and ships
36
What is the coppicing traditional forestry management method?
Give uses
- cutting trees to ground level on a cycle of 1-20 years depending on the use of the wood, to encourage more, thin growth
- the branches that regrow were used for:
e.g. baskets, fencing, charcoal, wall panels, roof rafters
37
What is the pollarding traditional forestry management method?
- similar to coppicing: trees are cut above ground level so the regrowing branches cannot be eaten by livestock. More, thinner
e.g. aesthetic reasons, animal fodder, firewood
38
Are coppicing and pollarding common?
there is currently little demand for coppiced/pollarded timber
39
Give an example of a wood being used
HMS victory, 1765
- required over 6,000 trees, mainly oak
40
How and why does modern commercial forestry emerge?
- as a society develops to become industrial, the demand and usage of timber changes
- demand for wood fuel may decline as people switch to ff or elec
- species-specific uses of wood from traditionally managed woodland often replaced by large-scale uses such as chipped wood or sheet construction material, and plywood for concrete shuttering
41
What are the ways in which modern commercial forestry is different to traditional forestry?
- harvesting methods changed from selective logging or cutting of small areas to large scale clear felling
- this reduces wildlife biodiv of the forest
- the existing natural woodland may be replaced with plantations/monocultures of selected species
42
What are the modern commercial forestry management methods?
- cultivation of non-indigenous species
- single species plantations
- close planting
- simple age structure
43
Explain cultivation of non-indigenous species as a modern commercial forestry management method
What are the issues?
- tree species selected for cultivation are often non-indigenous because they may be better adapted to env conditions or less likely to be vulnerable to pests or diseases damage
- less likely to support indigenous wildlife species because their inter-species needs for food, pollination, seed dispersal or habitats are less likely to be met
44
Give examples of cultivation of non-indigenous species for modern commercial forestry management
UK - Sitka Spruce and Douglas Fir (originally from N. America)
- used in construction, paper pulp and musical instruments
CENTRAL AMERICA - Teak (originally from Asia)
- indoor and outdoor furniture, decking
EAST AFRICA - Eucalyptus (originally from Australia)
- air freshener, respiratory relief, skin care and medicine/pharmaceuticals
45
Give characteristics and explain cultivation of single species plantations as a modern commercial forestry management method
- growing a monoculture of a single tree species can make managing a plantation easier, as all trees have similar water and soil requirements etc
- activities such as planting, thinning and felling can be carried out over large areas at the same time
46
Explain close planting as a modern commercial forestry management method
What are the issues?
- planting all the seedlings close together makes the trees compete with each other for light so they grow tall and straight which is important for large timber production and regularity
- the low light levels at ground level inhibit the growth of other plants that may compete with the trees for water or nutrients
- the loss of these plants and species that depend upon them reduces the wildlife diversity of the forest
47
Explain simple age structure of plantations as a modern commercial forestry management method
What are the issues?
- planting large areas of trees at the time makes tree management easy: the trees will all be of similar sizes and will all need similar management activities at the same time
- however, having trees of a similar size reduces the variety of abiotic factors compared with having a plantation with trees of different ages and sizes. This reduces the amount of ecological niches, and therefore reduces the diversity of the wildlife species that can survive
48
How does the simple age structure of modern commercial tree plantations affect when they are felled?
- the trees in commercial plantations are usually felled when the income will be greatest: simple age structure means more can be felled at once, and faster. = MAXIMUM INCOME - a whole areas can be cleared at once, while still leaving some of the younger areas for more income later
- this is normally when they are approaching full size and the growth rate is starting to decline
- this is very different from a natural forest which contains old trees with dead wood that supports many invertebrates and the species that feed on them such as woodpeckers
49
How much of the world's original forest area has been lost to human activities?
What is the rate of loss like?
1/3
Forest loss continues, but the rate has dropped in the last 30 years
50
What activities are included in deforestation?
any activities that cause a reduction in forest area
51
What are the two main causes of deforestation?
Give examples
- deliberate removal of forests to make space for another land use e.g. agriculture, urban development
- unsustainable exploitation: exploitation above the MSY
52
What does harvest mean?
What scale does it cover?
the removal of trees for a variety of uses
- may take up to 100y to reach the harvesting stage
53
What does regenerate mean?
the process of growing back what has been lost
54
What are the 3 major harvesting methods?
clear cutting
strip cutting
selective cutting
55
What is clear cutting?
How does it work?
cut down every tree in a selected area in a quick and efficient manner
- can create considerable damage such as the destruction of entire areas and soil erosion
METHOD:
large machines cut the trees, remove branches, cut logs into lengths and load them onto large trucks in the area
56
What is strip cutting?
How does it work?
harvesting trees in narrow strips to minimise damage and try to allow for natural forest regeneration
METHOD:
heavy machinery is used, leaving the sections between the strips uncut, especially among lakes and rivers to reduce soil and limit wind erosion
57
What is selective cutting?
How does it work?
harvest only a limited amount of trees that meet a certain criteria
- usually happens in multi-species forests
METHOD:
- one or two operators use chainsaws to cut down the trees on own property, reducing the scarring of the land
58
What are some example criteria for selective cutting?
- maturity
- height
- age
- diseased
etc etc etc
59
What are the pros of clear cutting?
- efficient and higher profit
- allows faster growth for species of trees that need full sunlight
- can reforest with fast growing trees
- can plan for a forest that controls pests and competing plants, improves seedbeds, and prevents soil problems
60
What are the cons of clear cutting?
- increased water pollution, flooding and erosion on steep slopes
- flooding often lowers the chances of seedlings growing
- removes essential habitats (large trees)
- regrowing forests = same age structure = less resistant to harsh weather
- no guarantee of regeneration plus env looks bad; VISUALS
- reduced biodiversity and wildlife suffers loss of ecosystem services and food etc
61
What are the pros of strip cutting?
- leaves more habitat than clear cutting
- allows for quicker forest regrowth
- natural regen within a few years because it reseeds on its own
- forest looks much healthier
- more sustainable harvest without widespread destruction
62
What are the cons of strip cutting?
- when trees are cut, seed source is lost
- bare strips still allow soil erosion and thinning
- still destroys large sections of the ecosystem
- not as efficient as clear-cutting, and therefore more expensive
63
What are the pros of selective cutting?
- supports more wildlife/species (bio)diversity by keeping ecosystems intact
- build up tolerance and resistance to disease and pests
- CO2 stored by trees will regen/replenish faster
- helps forest grow back faster
- reduces fire hazards and minimises soil erosion
- reduction in visual scarring
64
What are the cons of selective cutting?
- expensive and time-consuming
- some species will not regenerate as fast
- more exposure to weather damage e.g. ice, storms, fires
- lots of stumps and other tree debris left behind
- often removes genetically superior trees, whose seed is needed to keep forests healthy
65
Where is strip cutting most commonly used?
CANADA
- with black spruce in the Boreal forest, and mixed wood types in northern Alberta
66
What are some of the example things a forest manager may plan for?
MANY DIFFERENT GROUPS USING THE FOREST AND ITS RESOURCES IN MANY DIFFERENT WAYS AND PURPOSES
Some are concerned with:
- wildlife
- forest industry
- recreation
- wilderness
- fire control
- insect control
- watershed
All managers must consider and plan for the use, improvement, protection, and regeneration of the forest
67
How can selective logging be managed sustainably to maintain biodiversity (TRF)? (official)
- harvesting rate
- mixed species plantations
- indigenous species
- mixed age structure
68
What are the main reasons for unsustainable exploitation?
1. timber resources
2. fuel
3. livestock fodder
69
How has exploitation for timber become unsustainable?
Give examples
SOFTWOOD produced by conifers (e.g. pine, spruce, fir) is often produced sustainably with replanting to replace harvested areas in areas such as Scandinavia and Canada
- fast growing
HARDWOOD (e.g. teak, mahogany)
- slow growing = more difficult to manage hardwood plantations as it may take longer to produce a saleable crop
- therefore, it often comes from mixed forests that are clear felled and may not be replanted
70
How has forest exploitation for fuel become unsustainable?
Where may it be used
More people rely on wood as their domestic energy source than any other fuel
- not necessarily the fuel of choice but many people in LICs cannot afford alternative energy sources and have to use wood, even though its exploitation may be unsustainable
- high reliance as a domestic energy source in both LICs and HICs, and industry too in LICs
- in towns and cities, there may be a greater demand for charcoal that produces less smoke when burnt
- the production of charcoal involves partial combustion of wood with a shortage of air. Much of the energy value of the wood is lost in this process which increases the rate of forest clearance to satisfy the demand for energy
71
How has forest exploitation for livestock fodder become unsustainable?
It is unusual for forest areas to be cleared to provide livestock food, however:
- in LICs, in areas of mixed woodland and grassland, farmers may cut branches off trees if there is a shortage of ground-level grazing, to top up animal food supply
- if this exceeds the growth rate of trees then the forest may gradually be degraded and disappear
72
What are the features of sustainably managed forests?
- harvesting rates
- mixed species plantations
- indigenous species
- mixed age structure
- selective logging
73
Why are harvesting rates features of sustainably managed forests?
Give an example
the rate of resource removal must be no greater than the MSY
e.g. US - Washington Olympic Peninsula, Rayonier (company)
- harvests less than 4% of total forest area/year, ensuring volume cut is in line with the MSY
- often spans 150 years of continuous, replanted and harvested growth
74
Why are mixed species plantations features of sustainably managed forests?
Give an example
wildlife biodiversity is increasing by growing multiple species because there is an increase in food choices, inter-species relationships and niches
e.g. Brazil (Mixed Eucalyptus and Native Species):
- in the Atlantic Forest region, plantations combine fast-growing Eucalyptus with native timber species like Acacia mangium
- allows for sustainable wood production while promoting restoration, as seen in projects combining Eucalyptus with native, nitrogen-fixing trees to improve soil nitrogen and carbon (like Am)
75
Why are mixed age structures features of sustainably managed forests?
Give an example
having a plantation with trees of different ages produces a greater diversity of abiotic factors such as light levels, temp and wind velocity. This increases the biodiversity of other species living in the forest through new niche creation
e.g. Faskally Forest, Scotland:
- roughly 25-55 ha of early 20th-century planted mixture (Norway spruce, Scots pine, larch, Douglas-fir) was transformed into an uneven-aged structure managed under a selection system
- enhanced populations of wildlife such as red squirrels, buzzards, pine martens and siskins
76
Why are indigenous species features of sustainably managed forests?
Give an example
if indigenous species are cultivated it is more likely that other indigenous species will benefit (for example, birds and insect pred-prey cycle)
e.g. Hawaii (The Ukulele Restoration Project) - Koa trees
- supports ‘Akiapōlā‘au, a rare, endangered honeycreeper that relies specifically on Koa for foraging and nesting, using its specialized beak to extract larvae from the bark
- also supports Koa Moth, whose larvae feed on the foliage. May provide the food for the ‘Akiapōlā‘au
- also supports local production of traditional musical instruments which enhances local community culture
77
Why is selective logging a feature of sustainably managed forests?
Give an example
CLEAR FELLING
- clear felling a large area at one time is easy. It can be commercially advantageous if the trees have been grown as a single species monoculture as all the trees may be ready for harvesting at the same time
- in mixed-species plantations or natural forests, different trees may be ready for felling at different times
SELECTIVE LOGGING
- however, selective logging is more expensive because it is more labour intensive, but it gains the maximum benefit from the forest timber resource over longer time periods
- it is also good for wildlife because the removal of individual trees leaves smaller clearings which have a smaller impact on the survival of remaining wildlife populations. Wildlife that has lost its tree habitat will not have to move far to find a new habitat
e.g. Germany/Central Europe: Continuous Cover Forestry (CCF)
- widespread practice, allowing for the selection of individual trees to maintain a permanent forest canopy rather than clear-cutting
- ~79% of German forests are mixed-species, which are managed using structural principles and selective logging rather than large-scale clear-cutting
- approximately 6% of the total forest area is not used for timber production at all, allowing for natural development and maximum canopy cove
78
How can forests be exploited sustainably?
What might this involve?
Give examples
if harvesting ates and env impacts are carefully managed
- may involve combo of the env beneficial methods used in trad forest management with the commercially productive methods of modern plantation forestry
- the move to better forest management has been helped by growing understanding of forest importance
e.g. China, Cuba, Bhutan implement large-scale tree planting projects
BHUTAN: The Bhutan Ecological Society's Mountains to Mangroves initiative aims to plant over 10 million trees by 2030, with a focus on high-value native trees and fruit trees. The Million Trees Initiative, launched by the Bhutan Foundation, aims to plant 1,000,000 high-value plantation trees to regenerate fallow land and restore degraded forest
