Forest management and water interactions results from studies in … · 2017-09-29 · Forest and...

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


Hylocomiosa Myrtillosa Oxalidosaturf.mel.

Diffe

rence

fro

m c

on

tro

l, %

(b)

0

200

400

600

800

1000


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


Diffe

rence

fro

m

refe

ren

ce

pe

rio

d, %

(b)

-100

-80

-60

-40

-20

0

SOH WTH C WTH


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


BU1 ST1 ST2 VA VG

mg L

-1


Results – NH4-N

0.78 mg L-1Limit

Target – cyprinid waters 0.16 mg L-1

Target – salmonid waters0.03 mg L-1



Results –PO4-P

0

0,05

0,1

0,15

0,2

0,25

0,3

0,35

0,4


BU1 ST1 ST2 VA VG

mg L

-1


Target

0.3 mg L-1



Results - TSS

0

50

100

150

200

250

300

350

400


BU1 ST1 ST2 VA VG

mg

L-1


Target25 mg L-1

37 catchments in Finland 1st year 58 mg L-1

5 catchments in Latvia 1st year 184 mg L-1



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



Preliminary results – DOC, WAMBAF

demo site

0

10

20

30

40

50

60

mg L

-1

virs zem



Results – TSS, WAMBAF demo

area

0102030405060708090

100

mg L

-1

virs zem



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.

Forest management and water interactions results from studies in … · 2017-09-29 · Forest and...

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