Environmental Engineering Reference
In-Depth Information
Table 1
Description of studied sites in Riga
Distance of
tree's stems
to street (m) Status of trees in August 2005 and 2007
1 - Park (three trees) >50 2005, 2007: Healthy
a
2 - Hanzas 1 (three trees) ~2 2005: Damaged; 2007: damaged
3 - Hanzas 2 (three trees) ~2.15 2005: Medium damaged: 2007: medium damaged
4 - Elizabetes (five trees) ~0.7 2005: Three-damaged, two-healthy; 2007:
one-dead in 2006, two-damaged, two-healthy
5 - Kr.Valdemara (three trees) ~0.7 2005: Damaged; 2007: medium damaged
6 - Stabu 1 (three trees) ~0.6 2005: Damaged; 2007: damaged
7 - Stabu 2 (four trees) ~0.6 2005: Three-damaged, one-healthy; 2007:
three-damaged, one-healthy
8 - Basteja 1 (three trees) ~3.5 2005, 2007: Healthy
9 - Basteja 2 (three trees) 1.0-1.5 2005: Damaged; 2007: damaged; one tree dead
in winter 2008
10 - Raina 1 (three trees) ~7 2007: Healthy
11 - Raina 2 (three trees) ~7 2007: Healthy
12 - Brivibas 1 (three trees) ~1.5 2007: Medium damaged
13 - Brivibas 2 (three trees) ~7 2007: Healthy
14 - Brivibas 3 (three trees) ~1.5 2007: Medium damaged
15 - Brivibas 4 (three trees) ~7 2007: Healthy
a
Healthy: 0-15% crown necrosis; medium damaged: 20-70%; damaged: 75-100%.
Site
For each soil sample three sub-samples were obtained and thoroughly mixed, to
form one sample. Soil samples in the control site (Viestura Garden) were collected
under the perimeter of the crown of trees and leaves from several branches of
the crown.
Leaf samples were taken with telescopic scissors from leaves just reaching
maturity and full size. For each sample 50 leaves were collected from different
branches of trees along roadsides during the vegetation season of 2005 (June, July
and August) and 2007 (June and August).
Along with leaf sampling bioindication research was done to diagnose the eco-
logical status of
Tilia × vulgaris
. Leaf necrosis as percentage of damaged leaf area/
total leaf area was estimated in June and at the end of August. Intensity of crown
necrosis in percent was estimated in August.
Laboratory Analysis
Sample preparation
. The soil samples were stored at +4°C, then dried at +35°C for
2 days and sieved <2 mm. Leaves were washed with distilled water, dried at +60°C
and ground.
Soil extraction and plant tissue ashing
. Na and K in the soil samples were
extracted with 1 M HCl solution (soil-extractant mixture 1:5). Cl
−
content was
