Lidar data
In addition to the national lidar scans (2008-2015, point density 0.5
points m-2 and 2019-2025, point density 1-2 points
m-2), KCS has been scanned during different campaigns,
allowing for high resolution DEMs down to 0.5 m resolution and providing
detailed tree level data. The first specific scanning was conducted in
2006 with a point density of up to 10 points m-2. In
2008, the KCS was scanned as part of the BIOSAR campaign with the TopEye
system S/N 425 mounted on a helicopter, at a flight altitude of 500 m
above ground level for main strips and 250 m above ground level for
cross strips, using an average point density of approximately 5 points
m-2 in the main strips and 15 points
m-2 in the cross strips. In 2015, the KCS was scanned
by Terratec with the Optech Titan X sensor at a flight height around
1000 m giving a point density of on average 20 points
m-2. This sensor scanned at 3 wavelengths, 532 nm
(green), 1064 (NIR), 1550 nm (SWIR). In 2019, the KCS was scanned with
Riegl VQ-1560i-DW 532 nm (green) and 1064 (NIR) with an average point
density of 20 points m-2.
Experimental platforms
Unraveling how the climate, land-use and other environmental
perturbations can affect short and long-term patterns in hydrology,
water quality and biodiversity, requires more than just good empirical
data from the past and present. It will be equally important to generate
data from controlled conditions outside the natural range of variability
previously experienced, mimicking anticipated external forcings in the
future. Experimental manipulations in the field are of fundamental
importance in this respect, as they can mimick expected extreme
conditions and responses to future perturbations. This is needed to
enhance our mechanistic understanding and constrain model predictions.
The already existing infrastructure and large availability of land for
research at the KCS makes large-scale and long-term experiments
conceivable and relatively simple to conduct.
The Trollberget Experimental Area (TEA) was established in 2018
to test best practices for management of the historical ditch-network
and develop new methods to mitigate negative effects on freshwater
environments. The ~ 60 ha site is located 1 km from the
KCS and drains into the Krycklan River just downstream of C16. It uses a
replicated, catchment-scale approach to study four different research
questions concerning forest water management, of which three are
assessing the future of historic drainage ditches and one testing
different riparian forest buffer designs. Given the relevance of the
topic and the robustness of the experimental set-up a large set of
researchers and projects are now involved in this satellite site.
Artificial drainage of peatlands through ditches have dewatered millions
of hectares of northern peatlands for forestry. Recent estimates suggest
that up to 1 million km of wetland ditches in Sweden alone have been
created (Ågren and Lidberg 2019), many of which are now not functioning
(Hasselquist et al. 2019). The future fate of these drainage ditches can
be to: 1) clean them to ensure resumed resumed drainage, 2) ecologically
restore them to a more natural state, or 3) leave them unmanaged. At
TEA, we have created a side-by-side comparison of these three different
management options with the objective of determining their effects on
water quality and quantity as well as their role in altering the
land-atmosphere greenhouse gas balance. Specifically, we have the goal
of quantifying the impact of peatland forest harvest, ditch cleaning,
and filling-in of ditches (ecological restoration) on dissolved organic
matter export and quality, greenhouse gas exchanges, nutrient and
sediment export, export and speciation of mercury, as well as water
storage. Here we take a catchment-scale approach for monitoring dynamics
and export from our different treatments; six experimental catchments
with an average size of 10 ha are being monitored in TEA, where four
catchments in the nearby KCS sites serve as controls.
In addition, TEA includes a riparian buffer experiment with the goal to
directly compare the functioning of narrow (5 m) to wider (15 m)
buffers. Monitoring of nutrient export, sediments, riparian vegetation,
and greenhouse gas fluxes in the stream and riparian zone are being
conducted. The unique opportunity of comparing before and after
treatment as well as the differences in responses to buffer widths, will
allow for more informed management decisions in the future.
A lake –stream experimental facility in the central part of
KCS (Fig 1d) allows for controlled flooding/drought manipulations in a
110 ha catchment system. A water regulating facility at outlet of the
lake, just upstream of the sampling site C5, can be used to flood the
lake and dry out the 1400 m stream reach to the downstream sampling site
at C6 (Gomez et al. 2020), or alternatively to use the water reservoir
in the lake to test flooding conditions downstream (Leach and Laudon,
2019).
Soil frost experiment: The KCS supports the longest
(>17 years) ongoing soil frost manipulations experiment in
the world (Campbell and Laudon, 2019), contributing with knowledge
critical for interpreting how changes in winter conditions will affect
soils and streams. The ongoing experiment has for example been used to
study the effects DOC (Haei et al. 2012), CO2 emissons
(Öquist and Laudon, 2008), decomposition processes (Kreyling et al.
2013) and root distribution (Blume-Werry et al. 2016).
Lake mesocosms and experimental flumes: Although observational
studies have tremendously advanced our understanding of freshwater
systems, their disadvantages are that many parameters typically
correlate and that causality seldom can be determined with any certainty
(Downes, 2010). Therefore, experimental facilities are useful to
disentangle the effects of individual parameters or their combinations,
especially in situations of unimodal responses. In lake Stortjärn, a
floating experimental platform consisting of 16 cylindrical 700 L
enclosures submerged in the lake can be used to perform controlled
in-site experiments (Cordero et al. 2021). Experiments can be performed
concurrently on 5 lakes across Sweden as part of the SITES-AquaNet
infrastructure (https://www.fieldsites.se).
A set of 12 outdoor, experimental flumes (i.e. channels) were built in
2020 within the KCS and fed by water from an adjacent stream. Each
channel is 20 cm wide, 20 cm deep, and 15 m long. Water is pumped into
one collector tank and then distributed through four manipulation boxes,
allowing four different concurrent treatments with three replicates
each. The slope and flow of each channel is adjustable ranging from 0 ˗
1.5 degrees for slope and 0 - 1 L s-1 for flow. The
channels can also be experimentally heated using warming cables. The
bottom substrate in each channel is composed of local, natural gravel
and pebbles but can also be manipulated.
In addition to the water and soil experiments, over 50 long-term
forestry and biodiversity experiments are conducted within the KCS area.
The oldest of these still in use began in 1911 to test the effect of
different provenance of seedlings at this latitude, in order to better
understand plant survival and wood quality. Other experiments include
fertilization effects on leaf traits of understory shrubs (Palmroth et
al. 2014), the effect of biochar addition on plant communities (Gundale
et al. 2016), and thinning and fertilization effects on Scots pine
(Valinger et al. 2019).
Database and sample archive
The guiding principles of the KCS research infrastructure are open data,
data sharing, and always welcoming new researchers and field studies.
The Svartberget research station, run by the Swedish University of
Agricultural Sciences Faculty of Forestry offers full access to 2500 ha
of land within the KCS for new field studies, and close collaboration
with land-owners in the area allows for the establishment of new
sampling programs and large scale experiments.
For every water sample ever collected within the KCS research program,
duplicate samples have been stored at -18° C in acid-washed bottles for
chemical analysis, and at +4°C, in glass bottles for water isotopes. All
in all, the Krycklan archive contains over 25,000 unique samples.
Additionally,the KCS database contains more than 15 million datapoints
on water chemistry, and even more data from long-term high-resolution
timeseries on physical parameters. The KCS database builds on a concept
we call FAIR & Square (Laudon and Taberman, 2016), which is guided by
Data FAIR port requirements (https://www.datafairport.org/). While FAIR
stands for Findable, Accessible, Interoperable, and Reusable, ‘Square’
symbolizes the importance of acknowledging of the original data
producer. An important aspect of FAIR & Square is that we try to
provide clear, precise and standardized metadata that can answer
questions about “when, where, how, and why” samples have been
collected, analyzed and quality controlled.
An important principle in the FAIR & Square concept is to acknowledge
the effort that has gone into acquiring the data being shared. In short
we ask users to: 1) Always cite the original source of data used, 2)
acknowledge other studies that touch on similar aspects that your work
builds on, 3) do not distribute data to third parties in order to allow
updates/corrections and to avoid spreading erroneous data, and 4)
recognize the original data producer properly in acknowledgments if they
provided data, or by offering co-authorship if they contributed with
significant work, important ideas, and/or helped with essential
interpretation.
5.0 Directions for the future
At a time when our environment is under increasing pressure from global
change it is alarming that many leading field research infrastructures
are under increasing threat to be down-sized or even closed. Failure to
recognize recognize and prioritize the value of long term reasearch and
monitoring compromises the possibilities that science can contribut to
long-lasting soultions. Never before has the need been greater to
continue the collection of empirical data that together with past data
can provide baseline conditions before climate change obscures the clues
to how ecosystems functioned without this massive human influence .
Understanding the fate of surface and groundwater resources, carbon
exchange processes, and threats to biomass production are questions of
fundamental importance for the future. Instead, the trend in monitoring
is going the other way, where empirical studies are declining relative
to modeling-based analysis. While modeling will be an important part of
environmental science, models must be constrained, tested, and validated
by empirical field data to be useful. To cite Sherlock Holmes by Sir
Arthur Conan Doyle, ‘It is a capital mistake to theorize before one has
data. Insensibly one begins to twist facts to suit theories, instead of
theories to suit facts.’