Changes in forest composition between presettlement and present are the result of climate and anthropogenic factors, including introduced tree disease, fire suppression and land-use changes.
Study Area: western New York. Beech is the one of most abundant species in the study area.
Data Source: Presettlement and FIA
Table 1. Data Attributes for the Four Study Areas and Different Time Periods
WNY 1797-1799 PLSR WNY 2002-2007/FIA
Trees or lines 8792 Trees 2481 Plots 210
Table 2. The Two Most Abundant Species in Each of the Time Periods and
Datasets, Determined Using Percent of Trees (%) or Importance Values (IV)
WNY 1797-1799 2002-2007
PLSR (%) American beech Sugar maple
FIA (% and IV) Sugar maple Red maple
FIA (IVpredictions) White ash Sugar maple
2X CO2 climate (IV predictions) White ash Red maple
3.5X CO2 cliamte (IV predictions) Post oak White oak
Analytic Methods: aggregating tree species to a common taxonomic level, measuring compositional change between time periods for each study area, and comparing amounts of change between different types of transition.
Table 3. Forest Compositional Turnovers (FCTs*) between PLSR and Present (FIA)
WNY NA NA1
Plot % 46.3 47.2
Plot IV 47.4 48.1
*FCTs were calculated using all native species aggregated to the PLSR taxa (NA), and using only those taxa with a percent abundance or IV greater than or equal to 1.00 (NA1), the sums of which for that data type were then rescaled to sum to 100%.
Ecosystem Changes in Fuzhou City, China
Summarization of the ecosystem changes in Fuzhou, my hometown, a city in the southern China.
1. Rivers and water quality changes. Fuzhou has three major river systems. While the quality of inland rivers has improved in recent years by importing flow water and implementing other effective remediation, lakes, reservoirs and coastal waters are showing a trend of eutrophication owing to the increasing amount of nitrogen and phosphorus which results from unorganized discharge of sewage from communities, farmland and livestock farm.
2. Urban agglomeration impact on regional climate. Fuzhou has an increasingly intensive population density ( 69 m2 /person in the central city in 2000, 73 m2 /person in 2005 and 78 m2 /person in 2010). This urban agglomeration trend is bound to the local climate and is one of the main reasons for the tropical island effect.
3. Aggravating land degradation. 1) Declines in quality of arable land. Soil survey indicates that the short-term use of arable land and heavily