The effect of afforestation on water infiltration in the tropics, as ...

Classification <strong>of</strong> designs
1) True time series
2) Randomized treatments (blocked,
factorial etc.)
3) False time series with good
randomization
4) Flawed designs, e.g. no replication
(excluded)
Literature Search
Databases used (30-11-2005):
• Web <strong>of</strong> Science (1986-2005)
• BIOSIS Previews (1989-2005)
• CAB Abstracts (1973-2005)
Search syntax:
• topic=((hydraulic conductivit* or Infiltra* or
permeabilit*) and soil* and water and (forest* or
afforest* or reforest* or deforest* or agro$forest* or
oil palm* or palm oil* or rubber* or tree* or
shifting$cultivat* or slash$burn or shifting$cultivat*
or slash* or logging* or clear$felling or clearing* or
skid* or burn* or hauling* or woodland* or savan*))
Response ratios and 95% Confidence Intervals
Afforestation
Confidence Intervals for Response Ratio
(after/before)
0.00 1.00 2.00 3.00 4.00 5.00 6.00
Stud/Exp.
Reforestation
Selective
Logging
Tracks
Between tracks
Subtotal
5 11
3 7
6 18
Deforestation
Selective logging
Reforestation
Deforestation
Tracks
Between tracks
Subtotal
Permanent cropps
Shifting cultivation
Savanah
Subtotal
1 3
2 3
3 6
5 10
4 11
1 2
8 23
Afforerstation
Plantation
Agr<strong>of</strong>orest
Subtotal
2 8
3 6
4 14
higher after
Steps <strong>of</strong> a meta-analysis
Treatments
Effect sizes
Combined
<strong>effect</strong> size
Systematic review
Study 1
Study 2
Study 3
etc ...
-means
-variances
-number <strong>of</strong> samples
-<strong>effect</strong> sizes
-confidence intervals
4