Monitoring and modeling of forest ecosystems: the Estonian Network of Forest Research Plots / Metsaökosüsteemide seire ja modelleerimine metsa kasvukäigu püsiproovitükkide võrgustiku abil

Abstract Forest research has long traditions in Estonia that can be traced back to the 19th century. Data from long-term forest experiments are available since 1921. The first studies mainly focused on silvicultural treatments and application of such data for understanding and modeling ecological processes was limited. The Department of Forest Management of the Estonian University of Life Sciences started to develop the Estonian Network of Forest Research Plots (ENFRP) in 1995. Since then, plots have been continuously re-measured with 5-year interval. Approximately 100-150 permanent sample plots were measured annually. In 2014, the long-term research network consisted of 729 permanent sample plots, of which 699 have been re-measured at least once, 667 plots - twice and 367 plots - three times. The total number of trees recorded in the network database amounts to 130,479. The plots are systematically distributed throughout the country. Detailed dendrometric measurements including tree spatial distribution are part of the survey protocol. Initially the network was set up to produce suitable data for development of individual tree growth models for Estonia. The significance of the network for the Estonian forest research is continuously increasing and nowadays ENFRP is recognized as an important national research infrastructure.

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A retrospective look at 80 years of silvicultural research at Petawawa

The Forestry Chronicle ◽

10.5558/tfc75385-3 ◽

1999 ◽

Vol 75 (3) ◽

pp. 385-388

Author(s):

Steve D'Eon

Keyword(s):

Experimental Design ◽

Key Words ◽

Research Priorities ◽

Factorial Designs ◽

Forest Research ◽

Permanent Sample Plots ◽

Site Characteristics ◽

Over Time ◽

Long Term Studies

Canada's oldest forest research plot was laid out at Petawawa in 1918. Since then, hundreds of researchers have established plots, gathered data, and published results utilizing the Petawawa Research Forest. Many of the projects and plots were designed as long-term studies meant to endure and be re-measured over the decades. Although control plots were utilized, these early experiments were established prior to the benefits of repetition and experimental design. Later experiments were installed with three or more reps and factorial designs strengthening their analytical capabilities. Research priorities have shifted over time from documenting the results of a particular silvicultural treatment to understanding why silvicultural responses are obtained. Factors that influenced the continuance of some studies and the discarding of others are reviewed.Some studies achieved their original goals and have been continued for longer periods or utilized for additional goals. Characteristics such as tenure, experimental design, and site characteristics are described for several of these studies. Key words: long-term research, permanent sample plots, Petawawa

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Assessing model performance in forecasting long-term individual tree diameter versus basal area increment for the primary Acadian tree species

Canadian Journal of Forest Research ◽

10.1139/x11-139 ◽

2011 ◽

Vol 41 (12) ◽

pp. 2267-2275 ◽

Cited By ~ 7

Author(s):

Matthew B. Russell ◽

Aaron R. Weiskittel ◽

John A. Kershaw

Keyword(s):

Random Effects ◽

Mean Squared Error ◽

Growth Models ◽

Secondary Growth ◽

Model Performance ◽

Basal Area ◽

Nonlinear Mixed Effects Models ◽

Absolute Deviation ◽

Individual Tree

Tree basal area (ba) or diameter at breast height (dbh) are universally used to represent tree secondary growth in individual tree based growth models. However, the long-term implications of using either ba or dbh for predictions are rarely fully assessed. In this analysis, Δba and Δdbh increment equations were fit to identical datasets gathered from six conifer and four hardwood species grown in central Maine. The performance of Δba and Δdbh predictions from nonlinear mixed-effects models were then compared with observed growth measurements of up to 29 years via a Monte Carlo simulation. Two evaluation statistics indicated substantial improvement in forecasting dbh using Δdbh rather than Δba. Root mean squared error (RMSE) and percentage mean absolute deviation (MAD%) were reduced by 14% and 15% on average, respectively, across all projection length intervals (5–29 years) when Δdbh was used over Δba. Differences were especially noted as projection lengths increased. RMSE and MAD% were reduced by 24% when Δdbh was employed over Δba at longer projection lengths (up to 29 years). Simulations found that simulating random effects rather than using local estimates for random effects performed as well or better at longer interval lengths. These results highlight the implications that selecting a growth model dependent variable can have and the importance of incorporating model uncertainty into the growth projections of individual tree based models.

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Celebrating 80 years of the Permanent Service for Mean Sea Level (PSMSL)

Proceedings of the International Association of Hydrological Sciences ◽

10.5194/piahs-365-1-2015 ◽

2015 ◽

Vol 365 ◽

pp. 1-5

Author(s):

L. Rickards ◽

A. Matthwes ◽

K. Gordon ◽

M. Tamisea ◽

S. Jevrejeva ◽

...

Keyword(s):

Sea Level ◽

Tide Gauge ◽

Tide Gauge Records ◽

International Union ◽

Mean Sea Level ◽

Level Change ◽

The Mean ◽

Set Up ◽

The 19Th Century

Abstract. The PSMSL was established as a “Permanent Service” of the International Council for Science in 1958, but in practice was a continuation of the Mean Sea Level Committee which had been set up at the Lisbon International Union of Geodesy and Geophysics (IUGG) conference in 1933. Now in its 80th year, the PSMSL continues to be the internationally recognised databank for long-term sea level change information from tide gauge records. The PSMSL dataset consists of over 2100 mean sea level records from across the globe, the longest of which date back to the start of the 19th century. Where possible, all data in a series are provided to a common benchmark-controlled datum, thus providing a record suitable for use in time series analysis. The PSMSL dataset is freely available for all to use, and is accessible through the PSMSL website (www.psmsl.org).

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Plasticity as a Link Between Spatially Explicit, Distance-Independent, and Whole-Stand Forest Growth Models

Forest Science ◽

10.1093/forsci/fxab043 ◽

2021 ◽

Author(s):

Oscar García

Keyword(s):

Spatial Structure ◽

Growth Models ◽

Forest Growth ◽

Mean Field Approximation ◽

Future Research ◽

Size Distributions ◽

Ecological Processes ◽

Individual Tree ◽

Perfect Plasticity ◽

Advantages And Disadvantages

Abstract Models at various levels of resolution are commonly used for both forest management and ecological research. They all have comparative advantages and disadvantages, making desirable a better understanding of the relationships between various approaches. Accounting for crown and root morphological plasticity in the limit where equilibrium among neighbors is reached (perfect plasticity) transforms spatial models into nonspatial, distance-independent versions. The links between spatial and nonspatial models obtained through a perfect plasticity assumption are more realistic than ignoring spatial structure by a mean field approximation. This article also reviews the connection between distance-independent models and size distributions and how distributions evolve over time and relate to whole-stand descriptions. In addition, some ways in which stand-level knowledge feeds back into detailed individual-tree formulations are demonstrated. This presentation is intended to be accessible to nonspecialists. Study Implications Introducing plasticity improves the representation of physio-ecological processes in spatial modelling. Plasticity explains in part the practical success of distance-independent models. The nature of size distributions and their relationship to individual-tree and whole-stand models are discussed. A size distribution is a one-variable distribution; joint distributions for two or more trees depend on the distances between them unless spatial structure is negligible. Limitations of current individual-tree models and questions for future research are discussed.

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Windthrow following four harvest treatments in an Engelmann spruce - subalpine fir forest in southern interior British Columbia, Canada

Canadian Journal of Forest Research ◽

10.1139/x99-135 ◽

1999 ◽

Vol 29 (10) ◽

pp. 1547-1556 ◽

Cited By ~ 17

Author(s):

David J Huggard ◽

Walt Klenner ◽

Alan Vyse

Keyword(s):

Large Scale ◽

Basal Area ◽

Random Trees ◽

Abies Lasiocarpa ◽

Ecological Processes ◽

Individual Tree ◽

Subalpine Fir ◽

Engelmann Spruce ◽

Lower Height

We used transect surveys at a large-scale experimental site at Sicamous Creek, B.C., to measure the effects of five treatments on windthrow: 10-ha clearcuts, arrays of 1-ha patch cuts, arrays of 0.1-ha patch cuts, individual-tree selection cuts, and uncut controls. We also examined edge effects and conditions predisposing trees to windthrow. Windthrow of subalpine fir (Abies lasiocarpa (Hook.) Nutt.) in the 2.7 years following harvesting increased from 0.6% of basal area per year in uncut forest to 0.8-1.8% per year in harvested treatments, with highest rates in individual tree selection units and lowest rates in 0.1-ha patch-cut arrays. Engelmann spruce (Picea engelmannii Parry ex Engelm.) showed similar patterns of windthrow but lower rates (0.2-0.7% of basal area per year in harvested treatments). Windthrow was concentrated near north and east edges of 1-ha and 10-ha openings but was dispersed throughout the more uniform treatments. Windthrown trees did not differ from random trees in diameter but had lower height/diameter ratios, probably reflecting the greater windthrow observed in subxeric sites on complex, elevated topography. The rates and distribution of windthrow in different harvest treatments have implications for ecological processes, salvage, long-term windthrow potential, and mitigation possibilities.

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Planning a system of permanent sample plots for integrated long-term studies of community-based forest management

Banko Janakari ◽

10.3126/banko.v16i2.965 ◽

1970 ◽

Vol 16 (2) ◽

pp. 3-11 ◽

Cited By ~ 10

Author(s):

H Meilby ◽

L Puri ◽

M Christensen ◽

S Rayamajhi

Keyword(s):

Forest Management ◽

Key Words ◽

Research Note ◽

Managed Forests ◽

Community Based ◽

Permanent Sample Plots ◽

Long Term Studies

To monitor the development of four community-managed forests, networks of permanent sample plots were established in 2005 at sites in Chitwan, Kaski and Mustang Districts, Nepal. This research note documents the procedures used when preparing for establishment of the plot networks, evaluates the applied stratification of the forest on the basis of data gathered in pilot surveys conducted in the early 2005, and provides a discussion on the implications of the choices made. Key words: Community-managed forests; permanent sample plots; stratification; allocation; estimates Banko Janakari Vol.16(2) 2006 pp.3-11

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Effects of disk tillage on soil condition, crop yield and weed infestation

Plant Soil and Environment ◽

10.17221/4201-pse ◽

2011 ◽

Vol 48 (No. 1) ◽

pp. 20-26

Author(s):

M. Birkás ◽

T. Szalai ◽

C. Gyuricza ◽

M. Gecse ◽

K. Bordás

Keyword(s):

Winter Wheat ◽

Crop Yield ◽

Field Experiments ◽

Soil Layer ◽

Soil Condition ◽

Perennial Weeds ◽

Weed Infestation ◽

Set Up ◽

Different Levels

This research was instigated by the fact that during the last decade annually repeated shallow disk tillage on the same field became frequent practice in Hungary. In order to study the changes of soil condition associated with disk tillage and to assess it is consequences, long-term tillage field experiments with different levels of nutrients were set up in 1991 (A) and in 1994 (B) on Chromic Luvisol at Gödöllö. The effects of disk tillage (D) and disk tillage combined with loosening (LD) on soil condition, on yield of maize and winter wheat, and on weed infestation were examined. The evaluation of soil condition measured by cone index and bulk density indicated that use of disking annually resulted in a dense soil layer below the disking depth (diskpan-compaction). It was found, that soil condition deteriorated by diskpan-compaction decreased the yield of maize significantly by 20 and 42% (w/w), and that of wheat by 13 and 15% (w/w) when compared to soils with no diskpan-compaction. Averaged over seven years, and three fertilizer levels, the cover % of the total, grass and perennial weeds on loosened soils were 73, 69 and 65% of soils contained diskpan-compaction.

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Connectivity: insights from the U.S. Long Term Ecological Research Network

Ecosphere ◽

10.1002/ecs2.3432 ◽

2021 ◽

Vol 12 (5) ◽

Author(s):

David M. Iwaniec ◽

Michael Gooseff ◽

Katharine N. Suding ◽

David Samuel Johnson ◽

Daniel C. Reed ◽

...

Keyword(s):

Research Network ◽

Ecological Research ◽

Long Term Ecological Research ◽

The U.S

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Spectrum Based Power Management for Congested IoT Networks

Sensors ◽

10.3390/s21082681 ◽

2021 ◽

Vol 21 (8) ◽

pp. 2681

Author(s):

Kedir Mamo Besher ◽

Juan Ivan Nieto-Hipolito ◽

Raymundo Buenrostro-Mariscal ◽

Mohammed Zamshed Ali

Keyword(s):

Power Management ◽

Network Performance ◽

Channel Allocation ◽

Battery Life ◽

Packet Routing ◽

Data Packets ◽

Increasing Demand ◽

Iot Devices ◽

Set Up

With constantly increasing demand in connected society Internet of Things (IoT) network is frequently becoming congested. IoT sensor devices lose more power while transmitting data through congested IoT networks. Currently, in most scenarios, the distributed IoT devices in use have no effective spectrum based power management, and have no guarantee of a long term battery life while transmitting data through congested IoT networks. This puts user information at risk, which could lead to loss of important information in communication. In this paper, we studied the extra power consumed due to retransmission of IoT data packet and bad communication channel management in a congested IoT network. We propose a spectrum based power management solution that scans channel conditions when needed and utilizes the lowest congested channel for IoT packet routing. It also effectively measured power consumed in idle, connected, paging and synchronization status of a standard IoT device in a congested IoT network. In our proposed solution, a Freescale Freedom Development Board (FREDEVPLA) is used for managing channel related parameters. While supervising the congestion level and coordinating channel allocation at the FREDEVPLA level, our system configures MAC and Physical layer of IoT devices such that it provides the outstanding power utilization based on the operating network in connected mode compared to the basic IoT standard. A model has been set up and tested using freescale launchpads. Test data show that battery life of IoT devices using proposed spectrum based power management increases by at least 30% more than non-spectrum based power management methods embedded within IoT devices itself. Finally, we compared our results with the basic IoT standard, IEEE802.15.4. Furthermore, the proposed system saves lot of memory for IoT devices, improves overall IoT network performance, and above all, decrease the risk of losing data packets in communication. The detail analysis in this paper also opens up multiple avenues for further research in future use of channel scanning by FREDEVPLA board.

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