Global Change Impacts On Forests

Question 1

What is the main cause of the decline in forests as well as grasslands and scrublands ?

Answer 1

It is caused by agricultural expansion of crop lands and graze lands

Question 2

Currently what occupies the biggest portion of land ?

Answer 2

In the beginning it was forest but now it grazing lands ,then followed by corp lands, then forests with grassland and shrub lands occupying the smallest land space.

Question 3

Where is forest increasing and decreasing ?

Answer 3

Forests are increasing in Europe,USA, N Asia and China and decreasing in parts of the tropics and Canada

Question 4

Where can forests be found ?

Answer 4

Forests can be found in areas where precipitation is relatively high . ( drier areas= less trees)

Question 5

What is the difference between tropical forest and cool temperate forests in terms of carbon capture?

Answer 5

Tropical forests store carbon both in the biomass and in the soil (equal amounts)while cool temperate forests mostly store carbon in the soil

Question 6

Between carbon stored underground and carbon store in biomass which is released much quicker ?

Answer 6

Carbon in the soil tends to be released much slower than carbon stored in biomass(hence deforestation releases carbon much quicker into the atmosphere

Question 7

What are some of the climate factors affecting forests ?

Answer 7

Increased CO2
Increased temperature
Altered precipitation
Air pollution
Altered solid nutrient level

Question 8

Increased CO2 on forests .

Answer 8

The ,most common reaction to increased CO2 on forests is that they grow quicker . However it is worth it to know that these studies have only been conducted on only younger tress so there is very little information on how elevated CO2 levels affect older forests

Question 9

What are the impacts of increased temperature on forests ?

Answer 9

Plants usually operate with optimum temperatures and most trees in the tropics / other warm environments are at their optimum temperatures (which where everything is functioning at peak level. So an increase in temperatures in these areas is likely to negatively affect photosynthesis . Forests in cooler environments (eg. Tundra, boreal, evergreen needle leaves ) currently operate below their optimum temperatures (they function fine as is ) however an increase in temperature is like stimulate the plant to reach optimum temperature boosting photosynthesis and growth .

Question 10

How does precipitation impact forests

Answer 10

Net primary production of plants is strongly linked with precipitation( the wetter it is the more productive the forest is ).

Question 11

How does air quality affect forests ,?

Answer 11

What matters the most is ground surface ozone which is extremely toxic to plants .and is known as the most important air pollutant . Other pollutants such a NOx and SO2 also affect the ecosystems of forest mostly by altering soil chemistry .

Question 12

How does nutrient limitations affect forests?

Answer 12

The nutrient being limited is dependent on the temperate of the region. In cooler areas N is more limited ( because temperature are very cool and slows down soil organic matter activities) this is why when it gets warmer in cooler climates it may stimulate soil organic matter decomposition to release N.
in warmer climates P is the limiting nutrient ( because of the high temperatures and heavy rainfall , P leaches heavily out of the the soil.

Question 13

It is known that forests are getting younger shorter overtime which have negative consequences on both biodiversity and carbon seques. What are some of the drivers of these changes( forests becoming shorter ) ?

Answer 13

Change in Land use : the cutting down of forests for agricultural land uses .
Wood harvest : similar to deforestation ( harvesting of mature trees reduces the avenge height of forest s.
Wildfires
Pests and diseases
Warming and drought

Question 14

True or false: like in crops there is a pole ward increase in pests and diseases in forests that is increasing tree mortality .

Answer 14

True

Question 15

Why older trees more preferred

Answer 15

Younger trees do not store as much carbon and certain species thrive in certain climate conditions only provided by old growth forests and without those conditions could push some species into extension

Question 16

What is the reason for the increase in the biomass of Swedish forests by 100% over the past 100 years?

Answer 16

This can be attributed to efficient forest mgt ( which mostly involves clear cutting ( cutting down most of the trees /or a section at a time)

Question 17

What are some of the disadvantages of clear cutting ?

Answer 17

It gravely affects biodiversity: during cutting the whole ecosystem is disturbed massively and affects the continued growth of some species. Most of Sweden’s biodiversity is linked to old growth forests , which are then cut down using this mgt style.

Question 18

True or false: Half of of Sweden,s red list species are attributed to forest practices .

Answer 18

True

Question 19

What was the reason for no significant effects being observed with increased CO2 levels on mature Norway spruce trees?

Answer 19

This was because there was lack of Nitrogen , which meant that
Growth in this area only began to improve when fertilized . Which actualities the fact that nitrogen availability highly affects the growth these trees

Question 20

What was the reason for no significant effects being observed with increased CO2 levels on mature Norway spruce trees?

Answer 20

This was because there was lack of Nitrogen , which meant that
Growth in this area only began to improve when fertilized . Which actualities the fact that nitrogen availability highly affects the growth these trees

Question 21

Soil warming effects

Answer 21

This stimulates microorganisms which begin to decompose and release nitrogen

Question 22

What are some of the differences between boreal fennomscandinavian trees and Canadian boreal forests

Answer 22

Scandinavian forests are heavily managed while Canadian forest are managed only to a limited extent ( about 35 - 40% ).

Question 23

Bark beetles?

Answer 23

They are beetles that attack trees in the Canadian boreal forests that have been affected by drought . And have began affecting fennoscandinavian trees as well.

Question 24

What is browning in reference to Canadian forest ?

Answer 24

Browning is used to describe a reduction in tree canopy, where the area generally starts to become brown .

Question 25

Why is there higher mortality in species poor forests ?

Answer 25

Many species have different characteristics, advantages and adaptations. The more divers a forest is the more likely it is to withstand adverse climate impacts and environmental stressess

Question 26

True or false: warming stimulates growth in tropical trees .

Answer 26

False . Experiments she that they grow slower with warming

Question 27

What happened to tropical trees in El Niño years

Answer 27

There was no biomass increase during this time due to high temperatures and drought

Question 28

What apart current views of the Amazon

Answer 28

Long term positive effects of rising CO2
There is variability in broth due to weather season.
The negative effects of heat like stronger in the past decade

Question 29

What are the causes of the recent fire outbreaks in the Amazon?

Answer 29

Number one cause is human activity ( especially farming activities ( like land clearing)

Question 30

Why do tree in the Amazon have little fire protection

Answer 30

This is because fire is not naturally occurring hence they have very thin barks which cannot with stand temperature.

Question 31

True or false : a growing bark becomes fire resistant when it’s bark thickness exceeds 6mm.

Answer 31

True

Question 32

What are some of the indirect causes in the loss of Amazon forest ?

Answer 32

Growing demand for Brazilian beef and soybean .
New policies encouraging forest exploitation
Reduced penalties for deforestation
Reduced funding for environmental monitoring

Question 33

Drivers for deforestation differ between regions.

Answer 33

While agricultural commodities drive South American deforestation,shifting agriculture (slash and burn: forest is cleared to make space for temporary farm lands )is the dominant in African forest cover loss . Asia is a mixture of both agriculture commodities and forestry practices (logging for timber).

All these different drivers are driven by economic development , population growth , governance and land use technologies

Question 34

Forest benefits

Answer 34

They are the second largest carbon sinks

Question 35

What is the difference between crops and forests in terms of increasing CO2 uptake ?

Answer 35

Plants will go into oxidative stress but tree ps will grow quicker .

Question 36

What is the difference between crops and forests in terms of increasing CO2 uptake ?

Answer 36

Plants will go into oxidative stress but tree ps will grow quicker .

Question 37

What are the main temporal features of terrestrial carbon sinks ?

Answer 37

1.long term increasing trend in biomass due +in CO2
2. Large inter annual variability attributed to the Elniño years

Question 38

What are the other impacts of deforestation on trees

Answer 38

Higher deforestation =temperature increase because evapotranspiration is low and a lot energy goes into heat production.

Reforestation = higher evapotranspiration which leads to cooling

Question 39

How does deforestation affect the rainy season ?

Answer 39

It declines aerial water transport (from reduced evapotranspiration) which affects the seasons

Question 40

How does deforestation affect the rainy season ?

Answer 40

It declines aerial water transport (from reduced evapotranspiration) which affects the seasons