forest management and water interactions results from studies in … · 2017-09-29 · forest and...
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Forest management and
water interactions – results
from studies in Latvia
Zane Libiete, Arta Bardule, Edgars Jurmalis, Ivars Klavins, Zane
Kalvite
Latvian State Forest Research Institute «Silava»
V International Conference „FOREST AND WATER”Supraśl, Poland, 12-14 September, 2017
Forest and water in Latvia (1)
Baltic Sea drainage basin. From: Sweitzer et al. 1996
Latvia
Covers 3,8% of the Baltic Sea catchment area
~12,3 thousand rivers, with total length of 38 000 km
Forest cover - 52%
Forestry, wood processing and furniture manufacturing
represents 5,2% of GDP
Forests and water in Latvia
600 mm <N< 950 mm5% <W< 95%
rW,N= -0,24 r0,05= 0,11
Percentage of waterlogged forests:1 – 5-30%; 2 – 31-50%; 3 – 51-95%
Confined aquifer discharge areas
Drainage and forest productivity
Forests on dry mineral
soils49%
Forests on wet mineral
soils10%
Forests on wet peat
soils8%
Forests on drained
mineral soils19%
Forests on drained peat
soils14%
*According to NFI data
Area of forests in different growing conditions
Forest and water in Latvia (2)
Challenges related to forest
management and water quality
Forest infrastructure building
and maintenance
Intensified biomass
harvesting
Beaver population management
Intensified biomass harvesting
Aim and hypotheses
To test whether different types of clearfelling (WTH and SOH) have
significant and different impact on soil and water chemistry, forest
regeneration and development of ground vegetation.
Hypotheses:
• clearfelling will result in significant increase of dissolved N-
compounds in soil-, ground and streamwater;
• the content of dissolved N-compounds in the soil water will differ
significantly between plots with stem-only and whole-tree biomass
removal.
Libiete Z., Bardule A., Murniece S. and Lupikis A. (2017). Impact of clearfelling on dissolved
nitrogen content in soil-, ground-, and surface waters: initial results from a study in
Latvia. Agronomy Research 15(3), 767–787
Objects, plots and samples
SiteDominant tree
species
Mean diameter,
cm
Mean height,
m
Basal area, m2
ha-1
Standing volume before
felling, m3 ha-1
Hylocomiosa Pinus sylvestris L. 34 31 35.3 541.3
Oxalidosa turf.mel.Picea abies L.
(Karst.)31 25 17.4 315.0
Myrtillosa Pinus sylvestris L. 31 26 21.2 270.9
Soil water, groundwater,
streamwater:
pH; ammonium nitrogen
(NH4-N); nitrate
nitrogen (NO3-N) and
dissolved total nitrogen.
3 plots in one object – WTH,
SOH, control
Soil solution
Nitrate (a), ammonium (b), dissolved total nitrogen (c) content difference (%) from control
in soil solution at the study sites. WTH - whole-tree harvesting; SOH – stem-only
harvesting; C – control. Dark grey - 2012, light grey - 2013, white – 2014.
0100020003000400050006000
SOH WTH SOH WTH SOH WTH
Hylocomiosa Myrtillosa Oxalidosaturf.mel.D
iffe
rence
fro
m c
on
tro
l, %
(a)
-400
0
400
800
1200
1600
SOH WTH SOH WTH SOH WTH
Hylocomiosa Myrtillosa Oxalidosaturf.mel.
Diffe
rence
fro
m c
on
tro
l, %
(b)
0
200
400
600
800
1000
SOH WTH SOH WTH SOH WTH
Hylocomiosa Myrtillosa Oxalidosaturf.mel.D
iffe
rence
fro
m c
on
tro
l, %
(c)
Groundwater
Nitrate (a), ammonium (b), dissolved total nitrogen (c) content difference from reference
period (2012) in groundwater at the study sites. WTH - whole-tree harvesting; SOH –
stem-only harvesting; C – control. Grey – 2013, white – 2014.
-95
-90
-85
-80
-75
-70
SOH WTH C WTH
Hylocomiosa Myrtillosa
Diffe
rence
fro
m
refe
ren
ce
pe
rio
d, %
(a)
-80
-60
-40
-20
0
20
SOH WTH C WTH
Hylocomiosa Myrtillosa
Diffe
rence
fro
m
refe
ren
ce
pe
rio
d, %
(b)
-100
-80
-60
-40
-20
0
SOH WTH C WTH
Hylocomiosa Myrtillosa
Diffe
rence
fro
m
refe
ren
ce
pe
rio
d, %
(c)
Surface water
Nitrate (a), ammonium (b), dissolved total nitrogen (c) and dissolved organic nitrogen (d)
content difference from reference period (2012) in surface water at the study sites. Grey
– 2013, white – 2014.
Effect of sedimentation ponds
Several methods exist to decrease risk to water quality, aiming
to prevent erosion by reducing stream velocity and to stop
transport of particles, e.g.:Barriers;
Sedimentation ponds;
Overland flow areas;
Buffer areas.
Drainage system maintenance
One of the most common methods is the establishment of
sedimentation ponds before the inflow of the main ditch
in the water course.
Aims, objects and measurements
Aims:
1. Quantification of the amount of TSS
and nutrients leaving forest ecosystem
by drainage channels after drainage
system renovation.
2. Evaluation of efectiveness of standard
sedimentation ponds, as related to
water quality.
Measurements:
Water samples taken in 2012 –
first year after renovation - and in
2013 and 2014 – second and
third year after renovation (N-
NO3-, N-NH4
+, Ntotal, Ptotal, K+,
Ca2+, Mg2+, pH, DOC, TSS).
Repeated sampling in 2017.
Objects:
5 drainage systems renovated in
spring/summer 2012. Water
samples before and after
sedimentation pond
Results – NO3-N
0
0,2
0,4
0,6
0,8
1
1,2
1,4
1,6
1,8
2
PB AB PB AB PB AB PB AB PB AB
BU1 ST1 ST2 VA VG
mg L
-1
2012 before maintenance 2012 2013 2014 2017
50 mg L-1
Target
PB – before the pond
AB – after the pond
0
0,1
0,2
0,3
0,4
0,5
0,6
PB AB PB AB PB AB PB AB PB AB
BU1 ST1 ST2 VA VG
mg L
-1
2012 before maintenance 2012 2013 2014 2017
Results – NH4-N
0.78 mg L-1Limit
Target – cyprinid waters 0.16 mg L-1
Target – salmonid waters0.03 mg L-1
PB – before the pond
AB – after the pond
Results –PO4-P
0
0,05
0,1
0,15
0,2
0,25
0,3
0,35
0,4
PB AB PB AB PB AB PB AB PB AB
BU1 ST1 ST2 VA VG
mg L
-1
2012 before maintenance 2012 2013 2014 2017
Target
0.3 mg L-1
PB – before the pond
AB – after the pond
Results - TSS
0
50
100
150
200
250
300
350
400
PB AB PB AB PB AB PB AB PB AB
BU1 ST1 ST2 VA VG
mg
L-1
2012 before maintenance 2012 2013 2014 2017
Target25 mg L-1
37 catchments in Finland 1st year 58 mg L-1
5 catchments in Latvia 1st year 184 mg L-1
PB – before the pond
AB – after the pond
ST1
27.07.2017
27.06.2012
ST2
27.06.2012
27.07.2017
VG
27.06.2012
27.07.2017
Beaver dams
0
0,5
1
1,5
2
2,5
mg L
-1
virs zem
Preliminary results – NO3-N, WAMBAF
demo site
Virs – in the pond above dam
Zem – below the dam
Preliminary results – PO4-P, WAMBAF
demo site
0
0,005
0,01
0,015
0,02
0,025
0,03
0,035
0,04
0,045
May June July August September November December
mg
L-1
virs zem
Virs – in the pond above dam
Zem – below the dam
Preliminary results – DOC, WAMBAF
demo site
0
10
20
30
40
50
60
mg L
-1
virs zem
Virs – in the pond above dam
Zem – below the dam
Results – TSS, WAMBAF demo
area
0102030405060708090
100
mg L
-1
virs zem
Virs – in the pond above dam
Zem – below the dam
Effects of dam removal?
Beaver dam removal on the WAMBAF demo site, 30.08.2017
Dam removal at 2 «pilot» sites on
02.08.2016
Bebri 4
Bebri 6
0
0,05
0,1
0,15
0,2
0,25
0,3M
ay
Ju
ne
Ju
ly
Aug
ust
Aug
ust b
efo
re r
em
ova
l
Aug
ust a
fte
r re
mo
va
l
Aug
ust a
fte
r re
build
ing
Sep
tem
be
r
Ma
y
Ju
ne
Ju
ly
Aug
ust
Aug
ust b
efo
re r
em
ova
l
Aug
ust a
fte
r re
mo
va
l
Sep
tem
be
r
Bebri 4 Bebri 6
Mg L
-1
Preliminary results – NO3-N, «pilot»
sites, samples below the dam
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7M
ay
Ju
ne
Ju
ly
Au
gust
Au
gust b
efo
re r
em
ova
l
Au
gust a
fte
r re
mo
val
Au
gust a
fte
r re
bu
ildin
g
Se
pte
mb
er
Ma
y
Ju
ne
Ju
ly
Au
gust
Au
gust b
efo
re r
em
ova
l
Au
gust a
fte
r re
mo
val
Se
pte
mb
er
Bebri 4 Bebri 6
mg
L-1
Preliminary results – PO4-P, «pilot»
sites, samples below the dam
Preliminary results – DOC,
«pilot» sites
0
10
20
30
40
50
60
70
80
May
June
July
August
Au
gust b
efo
re r
em
ova
l
Au
gust a
fte
r re
mo
val
Au
gust a
fte
r re
bu
ildin
g
Se
pte
mb
er
Ma
y
Ju
ne
Ju
ly
Au
gust
Au
gust b
efo
re r
em
ova
l
Au
gust a
fte
r re
mo
val
Se
pte
mb
er
Bebri 4 Bebri 6
mg
L-1
Preliminary results – TSS,
«pilot» sites
050
100150200250300350400450
May
June
July
Augu
st
Augu
st be
fore
rem
oval
Augu
st afte
r re
moval
Augu
st afte
r re
build
ing
Septe
mber
May
June
July
Augu
st
Augu
st be
fore
rem
oval
Augu
st afte
r re
moval
Septe
mber
Bebri 4 Bebri 6
mg L
-1
Conclusions
1. Forest management-water intractions is an increasingly important and
very complicated research topic.
2. Sufficiently long monitoring period after the forest management
operations is necessary to evaluate the effects. Short-term
investgations may lead to inaccurate conclusions and overestimation
or, on the contrary, underestimation of the management effects.
3. Adverse effects of forest management on aquatic ecosystems are
possible, especially under the intensified forest management.
Therefore management goals and sustainability on different spatial and
temporal scales have to be carefully evaluated. Ecosystem service
approach may serve this purpose.
4. Water eccosystems are open ecosystems subject to impact from
various land uses, especially intensive agriculture. Combined effects of
different land use types and management regimes have to be
considered in relation to water quality. Cooperation among sectors is
needed in this regard.
Thank you for your attention!
Acknowledgement:
Studies No.1 and No.2 were conducted with the support of project Nr. L-KC-11-0004, “Methods and
Technologies to Increase the Capital Value of Forest”, in collaboration with the Forest Sector
Competence Centre and the Joint Stock Company Latvian State Forests.
Study No.3 was conducted within the Interreg Baltc Sea Region programme project «Water
management in Baltic forests» (WAMBAF).
We gratefully acknowledge support from Forest Research Station in Kalsnava Forest district in
performing forestry operations at the study sites.
Photos taken by Zane Libiete, Ilze Paulina, Edgars Jurmalis and Ivars Klavins are used in the
presentation.