Mary Anne Sword Sayer 1 Stanley J Zarnoch 2 and James D Haywood 1 US Forest Service Southern Research Station 1 Pineville Louisiana 2 Asheville North Carolina 2011 Ecological Society of America Annual Meeting August 712 2011 Austin Texas ID: 671880
Download Presentation The PPT/PDF document "Physiological mechanisms of sustained gr..." is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Physiological mechanisms of sustained growth despite crown scorch in a young longleaf pine plantation
Mary Anne Sword Sayer1, Stanley J. Zarnoch2, and James D. Haywood1U.S. Forest Service, Southern Research Station,1Pineville, Louisiana2Asheville, North Carolina
2011 Ecological Society of America Annual Meeting, August 7-12 2011, Austin TexasSlide2
Presentation outline
Introduction Longleaf pine (Pinus palustris Mill.) and fireLongleaf pine restorationObstacles to longleaf pine restoration
Experimental results from central Louisiana
Physiological mechanisms that sustain the growth of forests that are frequently burned.
How does season of fire impact these physiological mechanisms?
Physiology of sustained longleaf pine growth in response to fireSlide3
Introduction
Range once extended from east Texas to the Atlantic coastal plain of the U.S.Now found on 3.8% of its historical range.Physiology of sustained longleaf pine growth in response to fire
Adapted to, and benefits from frequent low intensity fire.
Ecosystem flora and fauna are perpetuated by fire.
Repeated fire every 2 to 5 years is used to manage longleaf pine ecosystems.
Range-Wide Conservation Plan for Longleaf Pine 2009. americaslongleaf.comSlide4
Increased interest in restoring longleaf pine
Introduction
Range-Wide Conservation Plan for Longleaf Pine calls for an increase in longleaf acreage from 3.4 to 8 million by 2024.
Regeneration success is likely.
Highly diverse ecosystems with 29 federally
listed
TES.
May be more tolerant of climate change than other southern pines (e.g., hurricanes, drought).
Photos: Glenn Hughes. Mississippi State University Extension Service.
ghughes@ext.msstate.edu.
Loblolly pine
Longleaf pineSlide5
Successful longleaf pine restoration depends on fire as a tool.
Obstacles must be overcome for fire to be welcome on private lands.Growth responses to fire are inconsistent and may be negative.
Introduction
Negative
○
Boyer (1987) South J
Appl
For
11:154-157.
○
Johansen and Wade (1987) South
J Appl For 11:180-184.○
Haywood (2009) For Ecol Manage
158:195-305.
○
Weise et al (1987) Res Note SE-347.
Neutral
○
Brockway and Lewis (1997) For Ecol
Manage 96:167-183.○ Weise et al (1987) Res Note SE-347. ○
Ford et al (2010) Can J For Res 40:1410-1420. Haywood (2011) New For 41:55-73.
heat damage to shallow roots
heat damage to vascular cambium
heat damage to buds
●
Out of prescription
●
Introducing fire / heavy fuel load
●
Unknown reasons Slide6
To determine if there are physiological variables that sustain growth after prescribed fire.
To determine if the seasonal variation of these physiological variables is related to forest production. To help land managers sustain forest production by manipulating these physiological controls using silviculture.Physiology of sustained longleaf pine growth in response to fire
Objectives and hypothesisSlide7
Hypothesis
Sustained growth depends on maintenance of physiological factors that control whole-tree carbon fixation. Objectives and hypothesisSlide8
Methods
Study siteTwo western Gulf coastal plain,
mesic
, upland sites.
Palustris
Experimental Forest
, Calcasieu Ranger District,
Kisatchie
National Forest,
Rapides Parish, LA.
Physiology of sustained longleaf pine growth in response to fire
Dominant understory vegetation included
Schizachyrium
scoparium
, S.
tenerum
, Helianthus
angustifolius
,
Heterotheca
graminifolia
.
Study Sites
longleafalliance.orgSlide9
Site
1 2 blocks age 13 yrs in November 2010
Ruston and
Malbis
fine sandy loams, Gore silt loam
Site 2
3 blocks
age
14
yrs in November
2010 Beauregard silt loam
Age 6 years
Age 7 years
Methods
Study site
Sites prepared by chopping or shearing/windrowing and burning.
Treatment plots, 22 x 22 m (0.048 ha).
Planted with container longleaf pine, 1.8 x 1.8 m. Slide10
Methods
Experimental design: repeated measures RCBD with 5 blocks.Control,
C
: No post-plant vegetation control.
3 vegetation management treatments
Burning,
B
: Prescribed fire in May 2003 and May 2005.
Herbicide,
H
: Post-plant herbicide application for 2 to 3 years, and hand felling of recovering woody vegetation at age 4 or 5 years.
Mid- to late May
1
st
flush
elongated
2
nd
flush
bud intact
Blocked by apparent soil permeability.Slide11
Results- crown scorch
Physiology of sustained longleaf pine growth in response to fire
Site 2 2003
Site 2 2005
2003
40-70% scorch
480 kJ/s/m
2
mild drought
2005
90% scorch
755 kJ/s/m
2
mild to moderate drought
Haywood (2010) New Forests 41:55-73.Slide12
Results- production
Annual groundline basal area growth
ANOVA of annual
groundline
basal area growth
H plots greater than C and B plots.
Magnitude of differences was less during drought.
Regardless of scorch, no difference between C and B plots.
Why didn’t crown scorch reduce tree growth?Slide13
Results-
foliage biomassLate summer, 4 months post-burning in 2003 and 2005.3 saplings per plot (45 per year).
1 sapling per one-third total height percentile.
Stem, branches, and age classes of foliage separated, dried, and weighed.
Destructive harvest in 2003, 2004, and 2005Slide14
Results-
foliage biomassANCOVA of foliage biomass with GLD as a covariateOld foliage: B plots less than C and H plots.
New foliage
: No difference among B, C, and H plots.
Total foliage
: No difference between C and B plots.
Foliage was re-established four months after crown scorch.
Old foliage: 2003, 2004, 2005
New foliage: 2003, 2004, 2005
Total foliage: 2003, 2004, 2005
Did rapid re-establishment of leaf area sustain sapling growth?Slide15
Results-
foliage biomassPercentage of foliage biomass by age class2003 and 2005: pct of 2
nd
flush foliage was greater on the B plots than the C and H plots.
ANOVA of pct foliage biomass by age class
2005
: pct of 1
st
flush foliage was greater on the B plots compared to the C and H plots.
1
st
and 2nd flush foliage growth may have been accelerated on the B plots compared to the C and H plots.
singed 1
st
flush foliage
2
nd
flush
bud intactSlide16
Results-
mechanisms of foliage re-establishmentShort-term increase in fascicle-level gas exchange
Example 1 in 2003-
mild drought,
mean
Ψ
July
pd
-0.34
MPa. morning vs. afternoon.
Example 2 in 2005-mild to moderate drought, mean
Ψ
July
pd
-0.73
MPa
.
uniform response.By October, gas exchange rates were similar between the C and B plots.
Amax1
before and after prescribed fire in 2003
A
max
1
before and after prescribed fire in 2005
1
3 saplings of mean height/plot, 10 dates in 2003-2005, detached fascicles, LiCor-6400 portable photosynthesis system, ANOVA.Slide17
Results-
mechanisms of foliage re-establishmentShort-term increase in fascicle-level gas exchangeRelated to stomatal
responses to water availability.
Prescribed burning in May led to an increase in leaf water status and gas exchange for up to a 3-month period.
g
w
decreased as leaf water status decreased.
Leaf water status and
g
w
increased after burning.
Sapling VPD and
g
w
on the Burn plots in 2005Slide18
Results-
mechanisms of foliage re-establishmentMobilization of stored root starchSeasonal pattern of southern pine root starch
accumulation
for storage
mobilization
for flush growth
Root starch before and after prescribed fires
1
Small woody roots
(2-10 mm diameter) were frozen and freeze dried.
Root starch was mobilized more rapidly on the B plots than the C and H plots.
1
3 saplings of mean height/plot, 12 dates in 2003-2005, enzymatic assay by
Dairyland
Laboratories, Inc. in Arcadia, WI, ANOVA.Slide19
Summary and Conclusions
Physiology of sustained longleaf pine growth in response to fire
Two potential mechanisms that sustain pine growth in frequently burned forests.
Increased leaf water status and gas exchange for up to three months after burning
.
Mobilization of stored root starch for the growth of new foliage after burning.
These mechanisms may accelerate foliage re-establishment after scorch.
These mechanisms are season-dependent.
Increased leaf water status is most beneficial during summer and early fall.
Root starch is least available for mobilization between August and December. Slide20
Summary and
ConclusionsPost-fire benefits to leaf area re-establishment and growth are available when the first flush is elongated but the second flush is intact and protected at the time of the burn.
A new study comparing spring and fall burning is underway to verify the physiological benefits of season of burning.Slide21
Mary
Anne Sword Sayer, msword@fs.fed.usUS Forest Service, Southern Research StationRWU-SRS-4158: Restoring and Managing Longleaf Pine Ecosystems