Forest Fertilization

Liming and fertilization as mitigation tools in declining forest ecosystems
R. F. Huett Water, Air, and Soil Pollution volume 44, pages93–118 “In central Europe the ‘new type’ forest damages have been observed since the mid 1970’s. Various investigations indicate that the declines are frequently associated with nutritional disturbances. Good correlations between the site specific substrate chemistry and the actual nutritional status of the trees/stands were found. To explain the sudden and widespread appearance of the forest declines, adverse anthropogenic impacts mainly due to elevated emissions of air pollutants and their atmospheric derivatives are hypothesized in combination with natural stress factors. Causal mechanisms include soil degradation due to accelerated soil acidification and increased nutrient leaching from the canopy of forest stands. Fertilization and liming experiments have demonstrated that a fast and sustained revitalization and restabilization of declining forest ecosystems marked by nutritional disturbances can be achieved. This is demonstrated by chemical and histological foliar analyses generally combined with a visible improvement of the phenotype. Soil analyses reveal a considerable positive change of the chemical soil status due to the site and species specific application of appropriate amounts of fast soluble fertilizers and lime. Considering these recent favorable findings, as well as based on observations from historic fertilization and liming trials nutrient supplementation and liming have become common tools to counteract the new type forest damages in West Germany.”

The effect of liming on quantity and chemical composition of soil organic matter in a pine forest in Berlin, Germany
Bernd Marschner & A. Waldemar Wilczynski 1991 Plant and Soil volume 137, pages229–236 “The study was carried out in a 40-yr old pine plantation on a Cambic Arenosol within the urban area of Berlin. Lime application (6.1 t ha-1) has led to a pH increase in the forest floor from 3.3 to 5.5 within one year and to a strong stimulation of macrofaunal and microbiological activity. Three years after liming, the C:N ratio of the forest floor decreased from 28 to 25 and P, Pb, Zn, Cu and Cd concentrations in organic matter increased significantly. The organic C pool of the forest floor was almost 7 t ha-1 lower in the limed plot which is attributed to increased microbial respiration. In the mineral soil too, C-pools are lower in the limed plot, amounting to 13.2 t ha-1 or 14% less than in the control. C:N ratios have narrowed significantly from 27–29 to 23 in 10–30 cm depth. The humic acid fraction is lower throughout the limed profile while the percentage of fulvic acids has increased significantly below 10 cm. The results point to severe losses of organic matter and to profound changes in its composition. This may be of consequences for site quality and leaching processes.”

Soil water chemistry as affected by liming and im fertilization at two Swedish coniferous forest sites
Hans‐Örjan Nohrstedt,1992 Scandinavian Journal of Forest Research Volume 7, 1992 – Issue 1-4 “Lime (1 000 kg/ha), NH4NO3 (150 kg N/ha) or a combination of both, were added to plots in two middle‐aged coniferous forest stands. Lysimeter studies were performed during four to six years after treatment. The concentration of inorganic N did not increase after addition of lime only. NH4NO3 fertilization, alone or in combination with lime, temporarily increased inorganic N, especially NO3. All treatments increased the acidity during the whole observation period when compared to the control. Addition of lime did not increase concentrations of Ca and Mg in the soil water. In contrast, N fertilization significantly increased the concentrations of both elements. The increases followed exactly the pattern of increases in NO3 concentrations. More research is needed to explain soil water acidification by a low lime dose. Application practices as regards placement within different parts of watersheds are an important subject to study. With our present knowledge, a low dose of lime cannot be recommended to counteract effects of acid deposition.

Liming as a mitigation tool in Germany’s declining forests—reviewing results from former and recent trials
R.F.Huettl & H.W.Zoettl 1993. Forest Ecology and Management Volume 61, Issues 3–4,Pages 325-338 “The so-called new types of forest damage in Germany are frequently related to ‘acid rain’ and enhanced atmospheric N deposition resulting in accelerated soil acidification and induced nutritional disturbances. To stop or reverse these effects liming is seen as an important mitigation tool. As forest liming is not new in Germany, the analysis of older liming trials indicated that liming generally leads to a long-term decrease of soil acidity, improvement of cation exchange capacity, base saturation, content of exchangeable Ca (when dolomite is used, also of Mg) and Ca/Al (Mg/Al) ratio. However, an increase of forest productivity due to a faster turnover of organic matter, was not achieved. Because of this fact and the observation that enhanced NO3 leaching losses may occur from limed soils, liming practices were practically discontinued in the 1970s. Owing to awareness of the new type of forest damage, the goals of liming were altered. Liming was now aimed at ‘compensating’ further acidic deposition at the soil surface and eventually reducing soil acidification and by these means increasing forest vitality. Nevetheless, teh NO3 constraint of liming remained, particularly when considering that nowadays, most of the German forests are impacted by relatively high atmospheric N deposition rates. Furthermore, it was found that liming can cause acidification of the subsoil and the displacement of heavy metal ions. Liming appears to stimulate fine root development in the uppermost soil layers, increasing the danger of frost and drought damage. As forest liming may be associated with ecological risks, a careful analysis concerning the need of liming should be carried out for each treatment area. Besides soil pH values, humus content, site history, actual atmospheric N deposition, N uptake capacity and nutritional status of the stand, forest floor vegetation as well as heavy metal load should be examined.”

>Base cation fertilization and liming effects on nutrition and growth of Vermont sugar maple stands
Timothy R.Wilmot et al., 1996.Forest Ecology and Management Volume 84, Issues 1–3, Pages 123-134… We conclude that in northern Vermont sugar maple stands on relatively infertile podzols with low pH, base cation limitations may be especially important in controlling sugar maple tree health or growth, while fertilization to ameliorate base cation deficiencies may be effective only at relatively high base cation addition rates.”

Forest ecosystem degradation and rehabilitation
Reinhard FHüttl & Bernd UweSchneider 1998 Ecological Engineering Volume 10, Issue 1, Pages 19-31 “The degradation of forest ecosystems may be attributed to various natural and anthropogenic factors such as climatical extremes, biotic stresses, selection of tree species, harvesting regimes, litter raking, off-site amelioration measures, former land use, air pollutant deposition and soil acidification, as caused by internal and external processes. An important factor for a loss of tree vitality are nutritional disturbances, eventually leading to declining stand stability and productivity. Therefore, the potential risks of forest fertilization as a major tool for rehabilitation of naturally or anthropogenically degraded ecosystems are discussed. In this respect, both salt-like and lime fertilizers contribute positively to revitalization of nutrient deficient stands. Experience indicates that forest liming may indeed counterbalance the progress of soil acidification as caused by high H deposition. However, specific reactions within the rhizosphere, the enhanced mineralization and loss of organic matter, the mobilization of heavy metals and Ma+ cations and an increased NO3 leaching are possible risks of forest liming. The results from experiments with salt-like fertilizers do not show any negative influence of dissolved aluminium on root vitality but succeeded in revitalization of nutrient deficient stands. In the case of sulfatic fertilizers, both increased sulfate leaching and storage of sulfate in the bulk soil have been reported. Therefore, selection of fertilizer has to be based on a precise characterization of site specific chemical and physical conditions, including relevant stand parameters. Besides fertilization, forest regeneration with site-adapted tree species may greatly contribute to the rehabilitation of forest ecosystems, since the capacity for storage of C and N and hence, for a closer nutrient cycling, may be improved significantly through this approach.”

Forest floor plant response to lime and fertilizer before and after partial cutting of a northern red oak stand on an extremely acidic soil in Pennsylvania, USA. PDF
M.C.Demchik & W.E.Sharpe 2001 “Liming and fertilization have been suggested as a means to remedy calcium (Ca) and magnesium (Mg) deficiencies on acidic, base poor forested soils. However, little is known about the effect such treatments may have on forest floor plants in North America. The objective of this study was to determine if additions of dolomitic lime (6600 kg/ha) and fertilizer (110 kg/ha K2O, 220 kg/ha P2O5) would alter forest floor plant communities. Forest floor plants were monitored for 2 years prior and 2 years after partial cutting on plots that received lime and fertilizer and on control plots. Forest floor plant diversity was unaffected by lime and fertilizer application. Deer-tongue grass (Panicum clandestinum L.), white violet (Viola blanda Willd.), blue violet (Viola sororia Willd.) and Carex spp. increased in number on limed and fertilized plots. While not affected by lime and fertilizer, numbers of dwarf ginseng (Panax trifolius L.) and mayflower (Maianthemum canadense Desf.) decreased after cutting, while numbers of fire cherry (Prunus pensylvanica L.) and hay-scented fern (Dennstaedtia punctilobula (Michx.)Moore) increased after cutting. A general trend toward decreased numbers of red oak (Quercus rubra L.) seedlings was also noted. While there was no effect of liming and fertilization on overall forest floor plant diversity, numbers of some species increased significantly.”

Long-term impact of liming on growth and vigor of northern hardwoods
Robert P. Long et al., 2011 Canadian Journal of Forest Research “Sugar maple (Acer saccharum Marsh.) is a keystone species in the northern hardwood forest, and decline episodes have negatively affected the growth and health of sugar maple in portions of its range over the past 50+ years. Crown health, growth, survival, and flower and seed production of sugar maple were negatively affected by a widespread decline event in the mid-1980s on the unglaciated Allegheny Plateau in northern Pennsylvania. A long-term liming study was initiated in 1985 to evaluate responses to a one-time application of 22.4 Mg·ha–1 of dolomitic limestone in four northern hardwood stands. Over the 23-year period ending in 2008, sugar maple basal area increment (BAINC) increased significantly (P ≤ 0.05) in limed plots from 1995 through 2008, whereas American beech (Fagus grandifolia Ehrh.) BAINC was unaffected. For black cherry (Prunus serotina Ehrh.), the third principal overstory species, BAINC and survival were reduced in limed plots compared with unlimed plots. Foliar Ca and Mg remained significantly higher in sugar maple foliage sampled 21 years after lime application, showing persistence of the lime effect. These results show long-term species-specific responses to lime application.”

Effects of Liming on Forage Availability and Nutrient Content in a Forest Impacted by Acid Rain
Sarah E. Pabian et al., 2012 PlosOne, June 28, 2012 “Acidic deposition and subsequent forest soil acidification and nutrient depletion can affect negatively the growth, health and nutrient content of vegetation, potentially limiting the availability and nutrient content of forage for white-tailed deer (Odocoileus virginianus) and other forest herbivores. Liming is a mitigation technique that can be used to restore forest health in acidified areas, but little is known about how it affects the growth or nutrient content of deer forage… Before liming, forage availability and several nutrients were below levels considered optimal for white-tailed deer, and many vegetative characteristics were related to soil chemistry. We observed a positive effect of liming on forb biomass, with a 2.7 fold increase on limed sites, but no biomass response in other vegetation groups. We observed positive effects of liming on calcium and magnesium content and negative effects on aluminum and manganese content of several plant groups. Responses to liming by forbs and plant nutrients show promise for improving vegetation health and forage quality and quantity for deer.

Terrestrial Liming As a Restoration Technique for Acidified Forest Ecosystems
Sarah E. Pabian et al., 2012. International Journal of Forestry Research “We studied the effects of liming on soils and forest songbirds as well as vegetation and calcium-rich invertebrate prey variables that were predicted to link birds to changes in soil conditions. We observed increases in soil pH, calcium, and magnesium, as well as in songbird abundances in response to lime application, with continuing increases through five years after liming. We observed an overall increase in snail abundance on limed sites, but an initial peak of a 23 fold increase three years after liming was reduced to an 11 fold increase five years after liming. We observed an increase in forb ground cover on limed sites, but liming had no effect on millipede abundance or other vegetation measures. Of the variables we measured, snail abundance was the most likely mechanism for the response in bird abundances. Because we observed continued benefits of liming up to five years post treatment, we concluded that liming is a very promising technique for restoring forest ecosystems impacted by acidic deposition.”

Rate of litter decay and litter macroinvertebrates in limed and unlimed forests of the Adirondack Mountains, USA
Timothy S.McCay et al., 2013. Forest Ecology and Management Volume 304, 15 September 2013, Pages 254-260 Highlights
• We studied litter decay and invertebrate abundance at limed and unlimed forests.
• Calcium content of litter was positively related to rate of decay.
•Rate of decay was slower at limed than unlimed plots.
•Liming reduced abundance of millipedes.
•Caution is advised when liming forests affected by acid deposition.

Ecological benefits and risks arising from liming sugar maple dominated forests in northeastern North America. PDF
Jean-David Moore et al., 2015 Environmental ReviewsVolume 23, Number 1, March 2015 “Liming, the application of carbonate materials (e.g., CaCO3, CaMg(CO3)2) to soils and surface waters, has been used extensively in Europe, and to a lesser extent in Canada and the United States, to mitigate the effects of acid deposition on forest and aquatic ecosystems. This literature review was conducted to assess the effects of liming on ecologically and economically important sugar maple dominated ecosystems of northeastern North America, where it is increasingly used to treat sugar maple dieback. Potential direct and indirect effects were considered to determine whether the use of liming to revitalize these forests could negatively affect other ecological parameters, including those in adjacent aquatic habitats. Based on current scientific literature, it is not anticipated that liming at rates of 1–3 t ha−1 would have major detrimental effects on these ecosystems. However, liming could have negative effects on northern hardwood forests with regard to earthworm invasions. The choice of liming as a mitigation tool should be made not only after weighing the potentially negative effects against the benefits of restoring sugar maple dominated stands in poorly buffered soils, but also after considering ecological components that could be lost or never recovered if an acidified forest ecosystem is not limed.”

Assessment of enhanced silicate rock weathering feasibility as a soil ameliorant and its influence on other terrestrial negative emission technologies
WO Garcia 2020. Dissertation zur Erlangung des Doktorgrades der Naturwissenschaften an der Fakultät für Mathematik, Informatik und Naturwissenschaften Fachbereich Geowissenschaften der Universität Hamburg

Helicopter Liming to Help Restore Acidified Forest Soil Productivity
C McCavour, S Sterling, K Keys, E Halfyard 2021 EGU General Assembly Conference Abstracts, EGU21-13660
Decades of acid deposition across northeastern North America has caused excess leaching of soil base cations (Ca2+, Mg2+, K+) and increases in bioavailable aluminum (Al3+) that, in combination, have resulted in widespread decreases in potential forest productivity. Despite major reductions in SO2 and NOx emissions since the 1990s, forest soils across the region have shown few signs of recovery from acid deposition impacts and it could take decades or centuries for natural recovery to occur. As a result, affected forests are stressed, less productive, and more prone to climate change-induced damage. Helicopter liming of upland forests may be an effective way to jump-start the soil recovery process…. These early chemical results are promising and further support the use of helicopter liming as an effective tool to combat lingering effects from acid deposition in acidified forests.

Long Term Effects of Forest Liming on the Acid-Base Budget (Full article available)
by Martin Greve et al., 2021. “In Rhineland-Palatinate (Germany), a high percentage of the forest area is located on poor soils with low buffering capacity. Extensive liming applications were performed to compensate for the negative consequences of acid deposition. In 1988, three experimental sites with untreated control plots and different liming treatments were established in coniferous stands to investigate the effectiveness of liming on acidification and its effect on forest ecosystems. Measuring deposition and seepage waters for 24 years allowed for calculating long-term acid-base budgets. The original approach was expanded by data from a detailed sampling of the forest stand and mineral weathering rates. Without liming, the acid load exceeded the buffer capacity by base cation release from silicate weathering during the whole observation period. As a result, there was a high release of aluminum. After liming seepage water output of organic anions, nitrate and sulfate increased in some cases, leading to a higher acid load. However, the carbonates of dolomitic limestone compensated for a higher acid load, resulting in less aluminum released compared to the control plots. Until sulfate output by seepage water declines and nitrogen emissions are reduced, liming and restricted biomass harvesting are required for forest stands on base poor soils to prevent further acidification, decline of nutrient stocks, and the destruction of clay minerals

Thirty-year effects of liming on soil and foliage chemistry and growth of northern hardwoods in Pennsylvania, USA
Robert P. Long et al., 2021. Canadian Journal of Forest Research “…The sustained effect of this one-time lime treatment shows the strong role of efficient nutrient cycling in forests and suggests that the benefits over a substantial portion of a stand rotation may increase the feasibility of operational liming.”