Table 1 Stream temperature characteristics in mature planted forest and harvested streams
From: Water quality in New Zealand’s planted forests: a review
Region | No. of sites | Riparian buffer | Monitoring period | Temperature (T) variable | Mature forest (°C) | After harvest (°C) | Change after harvest |
|---|---|---|---|---|---|---|---|
Northland1 | 4 | No | C: 3 years | Mean annual T | 12.7-13.9 | 14.5 & 15.1 | Significant increase in mean annual & maximum monthly temperatures c.f. control site |
Mean monthly maximum T | 14.9 | 20.2 & 18.6 | |||||
Daily maximum T | 26.3 & 23.3 | ||||||
Mean diurnal range (Jan-Feb) | 1.4-2.5 | 7.1 & 4.1 | |||||
Waikato2 | 5 | NA | C: Nov. - Dec. | Mean T | 13 | NA | |
Maximum T | 15.5 | ||||||
Waikato3 | 1-mature | Yes | C: Oct. - Jan. | Mean T, max. T, diurnal range | 16, 21.2, 3-4 | Water temperatures significantly higher at the harvest sites c.f. control sites | |
1-harvest | No | Mean T, max. T, diurnal range | 18.7, 30.2,10-12 | ||||
1-harvest | Yes | Mean T, max. T, diurnal range | 16.6, 23.9, 3-4 | ||||
Waikato4 | 12 | C: Dec. - Jan. for 13 years | Summer daily mean T | 16.7 | T increase 2-3.8°C c.f. control sites | ||
Summer daily max. T | 18.5 | T increase 4-7.3°C c.f. control sites | |||||
Bay of Plenty5 | 3 | NA | C: spring & autumn for 2 years | Mean T | 9.9-14.6 | NA | |
CNI6 | 6 | No | S: early summer | T range | 12-13.5 | 10.7*-16.0 | T 1-3°C higher in harvest c.f. shaded sites |
CNI7 | 8 | NA | S: early summer | T range | 10.8-13.8 | NA | |
CNI8 | 4 | No | S: over 2 years | T range | 6.5-12.2 | 7.8-13.8 | Little variation between harvested & control sites |
C: April - May | Mean T, diurnal range | 9.8-10.3, 0.5-2.0 | |||||
Gisborne9 | 4 | NA | C: February | Median T | 13.0-18.0 | NA | |
Hawke’s Bay10 | 3 | No | S: 5.5-6.0 years | Median T | 10.0-15.0 | pre- & post-harvest | No significant change in T after harvest |
Nelson11 | 1 - mature | S: Jul., Oct., Mar., Jun. | Mean min. T, mean max. T | 4.0-9.4, 6.8-13.1 | T up to 6.5°C higher in summer & 2.5°C lower in winter c.f. control site | ||
2 - harvest | No | 2.5-12.8, 5.8-17.4 | |||||
1 - harvest | Yes | 6.1-10.6, 7.1-12.1 | |||||
Nelson12 | 2 | NA | C: March - February | Mean daily winter T, summer T | 3-6, 11.5-14 | NA | |
Min. winter T, max summer T | 0.5-3.0, 15-18 | ||||||
Canterbury13 | 4 | NA | S: seasonal (n = 4) | Mean T | 7.3 | NA | |
Canterbury14 | 4 | NA | Oct - Jan (n = 4) | Mean T | 9.5 | NA | |
Westland | 4 | NA | Oct - Jan (n = 4) | Mean T | 10.7 | NA |