Chapter 13 FORESTS, LAND MANAGEMENT AND AGRICULTURE

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1 Chapter 13 FORESTS, LAND MANAGEMENT AND AGRICULTURE Figure Distribution of boreal forest in Eurasia. Simplified system of three forest formations is used, representing a gradient of decreasing productivity and species diversity from south to north. Note the irregular boundaries in the mountainous east and Scandinavia, southward displacement of zones in the colder east, and far north position of forest-tundra in central Eurasia.

2 Figure Current distribution of boreal forest in North America. A simplified three class system of forest formation is used comparable to Eurasia. Note the irregular boundaries and northward displacement of boundaries in the mountainous west, and the southward displacement of boundaries in the east. The area depicted in red represents a broad zone where the ratio of precipitation to evapotranspiration is nearly 1, and under 2 X CO2 scenarios the environment is projected to become too dry to support closed canopy boreal forest, and is converted to aspen "parkland," a woodland formation (Hogg 1995).

3 Figure Opposite warm season temperature trends between large-scale North American treeline reconstruction (Jacoby and D'Arrigo 1989) and combined recorded data and reconstruction in central Alaska (Barber et al. 2004).

4 Figure 13.04A. Forest species cover types of Russia. The area of central Eurasian transect (Krasnoyarsk Kray Region) is outlined. Figure 13.04B. Vegetation zones and forests of northern central Asia. Zones: A - Arctic desert; _ - Tundra; _ - Forest- Tundra; D - Northern open forest; E - Northern Taiga; F - Middle Taiga; G - Southern Taiga; H - Subtaiga; Forest- Steppe (grassland), and Steppe (grassland); I - Mountain Taiga; Species: 1 - pine; 2 -spruce, fir, cedar; 3 - larch; 4 -birch and aspen; 5 - others; 6 - nonforested. (From: Institute of Forests, Siberian Division, Krasnoyarsk, Russia).

5 Figure Average of mean annual temperature (MAT) of four climate stations (Dudinka, Essej, Khatanga, and Olenek) on the Taymyr Peninsula near the northernmost treeline in the world (Jacoby et al. 2000). Data from the CSM and CCC scenarios have been adjusted for the station mean for the grid cell and are depicted to The CSM scenario produces temperatures typical of a discontinuous permafrost region at the end of the scenario period, which would represent a change to a climate typical of areas with some commercial timber production. (Data from: ACIA data archive).

6 Figure Historic relationship between growth of Siberian larch and warm season temperature and future scenarios in the Taymyr Peninsula of Russia. Note the generally close relationship between the regional tree ring growth signal, here depicted as detrended and normalized index values, and the mean of May through September temperature. These trees are heat limited and display a positive relationship with temperature. The ECHAM scenario for the 21st century produces temperatures that would approximately double the rate of growth and make this marginal site a productive forest, The CSM scenario does not produce the same degree of warming, but would eliminate periods of severe growth limitation. (Data from: Jacoby et al. 2000).

7 Figure Relationship between summer and mean annual temperature at Reykavik Iceland for both the period of instrument record and the scenario period. The four depicted scenarios produce warmer temperatures in both the summer and annual mean temperature than the level recorded during the mid 20th century warm peak, but in this highly maritime area none of the scenarios greatly exceed those temperatures. Note the variability in the degree to which the different scenarios reproduce the historical relationship between the two vari- Figure Negative (opposite) relationship of temperatures at contrasting eastern and western portions of continents among the scenario stations. (Data from ACIA data archive)

8 Figure Relationship between summer and mean annual temperature at Goose Bay, Labrador, Canada, recorded data, and scenario data. All scenarios produce a magnitude of warming that substantially alters the moderately temperature-limited forest climate typical of the 20th century. The scenarios enter ranges of temperatures that would surpass thresholds for key factors such as outbreaks of insects that attack trees, new species, and altered ecosystem functions such as growth, fire, and decomposition. (Data from: D'Arrigo et al. 1996)

9 Figure Winter and mean annual temperature at Fairbanks, Alaska, recorded data versus the CCC scenario. Fairbanks data are a combination of University Experiment Station ( ) and Fairbanks Airport ( ). The CCC scenario develops a relationship between the seasonal temperatures not seen in the record, a disparity that widens with time. Different models have different strengths and weaknesses and all should be applied with an awareness of limitations, circumstances in which they perform well, and novelties that could affect assessments of key climate-dependent processes. (Data from: National Weather Service) Figure Site locations of dendroclimatic network of the Asian Subarctic (circles) and millennial-length chronologies (stars).

10 Figure Variations of temperature proxy records in circumpolar regions of the Northern Hemisphere: 1- according to data in Overpeck et al., (1997), 2 -data for Asian Subarctic (see Figure for locations of sites). Figure Long-term changes of tree-ring growth in high latitudes of the Northern Hemisphere. 1)- data from Esper et al. (2000); 2)- data from combined treeline chronology for east Taymir and

11 Figure Comparison of multi-millennium length Taymir tree-ring chronologies (absolute and "floating") (d) with other late Holocene paleotemperature records. a) Record of summer melting on the Agassiz Ice Cap, northern Ellesmere Island, Canada; b) Summer temperature anomalies estimated from the elevation of 14C dated sub-fossil pine wood samples in the Scandes mountains, central Sweden; c) Paleotemperature reconstruction from oxygen isotopes in calcite sampled along the growth axis of a stalagmite from a cave at Mo i Rana, in northern Norway. (redrawn from Figure 6 in Bradley 2000).

12 FFigure Annual temperature anomaly reconstructed from white spruce at North American treeline. For details of reconstruction technique see D'Arrigo (1996, 2001) and Jacoby, G., and R. D'Arrigo, (1989). Figure Warm season temperature regimes and regime shifts in central Alaska Note that the first half of the 20th century experienced extended periods of cool summers, which relieved moisture stress of low elevation white spruce. The mid 19th century reconstruction as warm is out of phase with overall northern hemisphere means, but is strongly established by the proxies (13C isotope and maximum latewood density) used in the reconstruction (Barber et al. 2000, Juday et al. 2003).

13 Figure Tree sample localities along the Central Eurasian IGBP transect (Yenesi meridian). Figure Statistically significant correlations between tree-ring increments and climatic variables (typical climatic response functions) for different vegetation zones of central Eurasia along a north/south transect. Note the potential alternative outcomes of climate warming depicted. A warmer climate could result in the replacement of existing forest vegetation zones in sequence (linear response) or novel ecosystems could appear (non-linear response) (Data from: Vaganov 1989, Vaganov et al. 1985, 1996, Panyushkina et al. 1997).

14 Figure Historic and reconstructed relationship between white spruce growth and summer temperature at Fairbanks, Alaska, and climate scenarios. The tree growth sample includes 10 stands across central Alaska. Summer temperature is an excellent predictor of white spruce growth. Because higher temperatures are associated with reduced growth and growth is the dependent variable, the temperature scale (left axis) has been inverted. Given the historical relationship between the variables and the scaling of these axes, the scenario temperatures can be read to infer approximate level of growth (right axis) possible in the future. The CSM is the coolest end member of the 5 scenarios for this grid cell, and it produces warm temperatures that would very likely depress growth to a level at which stress-related mortality factors, especially tree-killing insects, would be extremely high. The CCC is the warmest end member of the 5 scenarios for this grid cell, and it produces temperatures at the end of the scenario period below the empirical level of zero growth, and which would very likely not allow the species to survive. (Data from: Barber et al. 2004; ACIA data archive).

15 Figure Historic relationship between white spruce growth and mean of warm season temperature (Jun Jul Sep and - 1 Apr) with climate scenarios for central and northern Labrador, Canada. Both scenarios produce warming and inferred levels of tree growth that have not been experienced in this area in historic times. (Data from: D'Arrigo et al. 1996)

16 Figure Correlation of black spruce radial growth and Fairbanks mean monthly temperatures from four permafrostdominated sites in central Interior Alaska. On two of the sites (A) and (C) the relationship of tree growth and summer warmth is strongly negative. At one site (D) growth is positively related to winter temperature, and at the remaining site (B) winter (February) warmth is positive but April is negative. (Data from: G. Juday and V. Barber, Bonanza Creek LTER data archive).

17 Figure Relationship of radial growth of black spruce at Caribou-Poker Creek Research Watershed and a 2-month climate index, the mean of April and February 2 years prior. The smoothed (5-year running mean) values are highly correlated during the 20th century, suggesting that tree growth of this species and at sites similar to these could be predicted from scenario values. While warm February temperatures favor growth, warmth in April depresses growth. Under strong warming in the late 20th century, growth of this species has declined because the negative influence of April is stronger. (Data from: G. Juday and V. Barber, Bonanza Creek LTER data archive).

18 Figure Relationship of radial growth of black spruce at Fort Wainwright and a 4-month climate index (mean of January, previous January, previous February, and previous December at Fairbanks, Alaska. The smoothed (5-year running mean) values are highly correlated during the 20th century. This is one of the few species and site types in central Alaska for which the empirically calibrated growth rate can be inferred to improve under the warming climate scenarios. However, this permafrost site is very near thawing, and warming of the magnitude depicted in the scenarios would probably initiate thawing during the scenario period, leading to widespread ground subsidence and tree toppling. (Data from: G. Juday and V. Barber, Bonanza Creek LTER data archive)

19 Figure Relationship of summer temperatures at Fairbanks and relative growth of black spruce on Alaska Native owned land, Toghotthele Corporation, in central Alaska. The mean of three summer months is an excellent predictor of tree growth, with warm years resulting in strongly reduced growth. Conventions are the same as Figure By the end of the scenario period, temperatures that would not permit the species to survive are produced by the scenarios. (Data from: G. Juday and V. Barber, Bonanza Creek LTER data archive).

20 Figure Location of 14 Scots pine tree-ring width chronologies. N = Nikkaluokta, AJ = Angerusjärvi, LY = Lycksele, ST = Stortjäderbergsmyran, J = Jämtland, ÅÖ = Årsön, TS = Tannsjö, SK = Skuleskogen, N = Norberg, BM = Bredmossen, SH = Stockholm, HM = Hanvedsmossen, GH = Gullhult, AM = Anebymossen.

21 Figure Standard chronologies (age de-trended and normalized with long-term mean set to 1.0 and standard deviation on 1.0) of Scots pine tree-ring width chronologies in Sweden. Vertical axis is in units of standard deviation (departure from mean growth). Thick line is 11-year running average, d denotes chronologies from dry sites and w denotes chronologies from wet, peatland, sites. Curves express the degree of growth at any time relative to the long-term mean of the sam - ple. Note the synchronous late 20th century decline. (Data from: Linderholm 2002, Linderholm et al. 2002, Linderholm et al. 2003).

22 Figure Timing of climate events that release spruce bark beetles from population limits compared to actual outbreaks of bark beetles during the period of record in the 20th century. Warm summers permit high hatching success and rapid maturation of beetles, lack of cold winters provides for high survivorship and early breeding and beetle development. Stressed host tree populations are less able to resist attacks. Beetle outbreaks lag one or two years behind sustained warm intervals. The beetle outbreak in the last decade of the 20th century was promoted by the strongest sustained climate signals in the record, and the subsequent outbreak was the largest single episode of insect-caused tree mortality in the history of North America. (Data from: E. Berg, personal communication; Witter et al. 2004; National Weather Service, Homer Airport station)

23 Figure Dynamics of polar treeline on the Yamal Peninsula in Siberia. (a) relative distance of sampled tree remains from the present position of northernmost open stands of larch in river valleys. (b) Radiocarbon date and number of samples. Proposed division of the Holocene into three stages is indicated. (Data from Hantemirov and Shiyatov, 1999).

24 Figure Reconstruction of polar treeline dynamics on the Yamal Peninsula from 2000 B.C. Latitude of recovered samples is indicated by year. (Data from: Hantemirov, Shiyatov and Surkov, in press).

25 Figure Change in proportion of subfossil remains made up of spruce compared to larch in Yamal Peninsula samples.

26 Figure Altitudinal displacement of the upper treeline in the Polar Ural Mountains during the last 1150 years (Data from: Shiyatov 2003).