Fire and insects are natural disturbance agents in many forest ecosystems, often interacting to affect succession, nutrient cycling, and forest species composition. We review literature pertaining to effects of fire-insect interactions on ecological succession, use of prescribed fire for insect pest control, and effects of fire on insect diversity from northern and boreal forests in North America. Fire suppression policies implemented in the early 1900s have resulted in profound changes in forest species composition and structure. Associated with these changes was an increased vulnerability of forest stands to damage during outbreaks of defoliating insects. Information about the roles that both fire and insects play in many northern forests is needed to increase our understanding of the ecology of these systems and to develop sound management policies.

We investigated the effects of nitrogen fertilization upon the concentrations of nitrogen, condensed tannin and phenolic glycosides of young quaking aspen (Populus tremuloides) leaves and the quality of these leaves as food for larvae of the large aspen tortrix (Choristoneura conflictana), a Lepidopteran that periodically defoliates quaking aspen growing in North America. Nitrogen fertilization resulted in decreased concentrations of condensed tannin and phenolic glycosides in aspen leaves and an increase in their nitrogen concentration and value as food for the large aspen tortrix. These results indicate that plant carbon/nutrient balance influences the quality of aspen leaves as food for the large aspen tortrix in two ways, by increasing the concentrations of positive factors (e.g. nitrogen) and decreasing the concentrations of negative factors (eg. carbon-based secondary metabolites) in leaves. Addition of purified aspen leaf condensed tannin and a methanol extract of young aspen leaves that contained condensed tannin and phenolic glycosides to artificial diets at high and low levels of dietary nitrogen supported this hypothesis. Increasing dietary nitrogen increased larval growth whereas increasing the concentrations of condensed tannin and phenolic glycosides decreased growth. Additionally, the methanol extract prevented pupation. These results indicate that future studies of woody plant/insect defoliator interactions must consider plant carbon/nutrient balance as a potentially important control over the nutritional value of foliage for insect herbivores.

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The financial crisis has heightened interest in the question of how banks operate. This had been neglected by economists and finance researchers, but thanks to the crisis a wider debate on this issue seems to be the ‗new normal'. Over the past century and a half, the role of banking in the economy has been described by three different theories, which are differentiated by their accounting implications. The currently dominant theory is the financial intermediation theory of banking, which says that banks collect deposits and then lend these out, without any power to create money, just like other non-bank financial intermediaries. The fractional reserve theory of banking says that each individual bank is a financial intermediary, gathering deposits and then lending these out without the power to create money, but the banking system collectively is able to create money through the process of ‗multiple deposit expansion' (the ‗money multiplier'). The credit creation theory of banking says that banks are not financial intermediaries and do not gather deposits to lend out, but instead each individual bank has the power to create credit and money out of nothing. Eminent scholars have been supporting each one of these different theories. Recently, the Bank of England (2014) argued that textbooks have been wrong in their presentation of banks, and that the credit creation theory is, after all, correct. Needless to mention, the question which of the three theories is correct has major implications for economics, finance, monetary and general government policy and bank regulation. The Basel approach has been predicated on the veracity of the financial intermediation theory. Yet, proponents of each of the theories -including the recent intervention by the Bank of England -merely assert their viewpoints. So far only one empirical test exists. It is the purpose of the present paper to present another empirical test of the three theories, using a different methodology. Analysing bank operations and bank accounting via the bank's annual accounts reporting software, which allows the control of all other factors, it is found that the financial intermediation and the fractional reserve theories of banking are rejected by the evidence. Policy implications are discussed, in particular for regulating bank capital adequacy as a tool to avoid banking crises. JEL Classifications: E30, E40, E50, E60 AbstractThe financial crisis has heightened interest in the question of how banks operate. This had been neglected by economists and finance researchers, but thanks to the crisis a wider debate on this issue seems to be the ‗new normal'. Over the past century and a half, the role of banking in the economy has been described by three different theories, which are differentiated by their accounting implications. The currently dominant theory is the financial intermediation theory of banking, which says that banks collect deposits and then lend these out, without any power to create money, just like other non-bank financial intermediaries. The fr...

In subarctic forests, birch (Betula) trees respond to severe (50—100%) manual defoliation by delayed inducible resistance (DIR). This plant response to defoliation is characterized by a decline in the nutritional quality of leaves for immature insects for several years after defoliation events, and concomitant changes in leaf chemistry that may be detrimental to insect nutrition, that is, a decline in leaf nitrogen and an increase in leaf phenols. Two explanations of delayed inducible resistance have been proposed. (1) The active defense response hypothesis claims that delayed inducible resistance is an active response to defoliation per se rather than merely a passive consequence of recovery from the stress of severe defoliation. (2) In contrast, the carbon—nutrient balance (CNB) hypothesis claims that delayed inducible resistance is caused by nutritional stress resulting from severe defoliation. We used two experiments to test these hypotheses. (1) In a three—way factorial field experiment we reared spear—marked black moth (Rheumaptera hastata) larvae on Alaska paper birch (B. resinifera) saplings that had experienced combinations of 100% manual defoliation and fertilization with N and P in previous years, and measured larval survival and pupal mass. In association with these measurements of larval performance, we assayed leaf condensed tannin levels and the concentrations of N and P in leaves, and correlated the results of these assays with larval performance. (2) In a laboratory experiment we tested the biological activity of condensed tannin and linalool, the major secondary metabolites of Alaska paper birch leaves, by treating leaves collected from previously undefoliated Alaska paper birch saplings with combinations of condensed tannin and linalool, and measuring the performance of spear—marked black moth larvae reared on these leaves. Our results supported predictions of the carbon—nutrient balance hypothesis. We found that fertilization with nitrogen, the nutrient limiting growth of Alaska paper birch in our study site, mitigated delayed inducible resistance, and that condensed tannin is likely to be the major chemical cause of delayed inducible resistance in Alaska paper birch. In our field experiment we also found that fertilization of Alaska paper birch with phosphorus, a nutrient that does not limit the growth of Alaska paper birch in our study site, affected levels of condensed tannin in leaves and the sapling's defoliation history influenced this effect. Thus, future studies of the effects of mineral nutrition on secondary metabolite production by woody plants and their responses to herbivory should consider nutrients that do not limit growth in addition to those that do limit growth.