Frida I. Piper

Universidad de Talca · Instituto de Investigación Interdisciplinario

Interactions between plants and herbivores are central in most ecosystems, but their strength is highly variable. The amount of variability within a system is thought to influence most aspects of plant-herbivore biology, from ecological stability to plant defense evolution. Our understanding of what influences variability, however, is limited by sp...

Individual tree species might affect underground soil properties to favor the decomposition of their own litter. However, in some studies, monospecific litter decomposed faster underneath multispecific canopies than under canopies of the same species as the litter, suggesting that plant diversity in the overstorey creates a more favorable decomposi...

Trees in dry climates often have higher concentrations of total non-structural carbohydrates (NSC = starch + soluble sugars) and grow less than conspecifics in more humid climates. This pattern might result from growth being more constrained by aridity than the carbon (C) gain, or reflect local adaptation to aridity, since NSC fuel metabolism and e...

Premise: Climate change may lead to carbon (C) stress (negative C balance) in trees. Since non-structural carbohydrates (NSC) are required during spring's metabolic reactivation, C stress might delay the budbreak timing. This effect can be anticipated to be greater in shade-intolerant than in shade-tolerant species, owing to the faster C economy o...

Nonstructural carbohydrates (NSCs) mediate plant survival when the plant's carbon (C) balance is negative, suggesting that NSCs could predict plant survival under C stress. To examine this possibility, we exposed saplings of six temperate tree species to diverse levels of C stress created by the combination of two light conditions (full light avail...

The effect of shelter tubes on plant performance has been widely studied. Although, the role of shelter tubes in alleviating the effects of drought and high-irradiance stresses during seedling establishment has been less studied than its effect on survival. The present study compares the effects of shelter tubes with different light transmissivitie...

Wood density (WD), a key trait in the trait‐based approach of plant ecology, represents a carbon investment trait that varies across species and reflects a trade‐off between metabolism and longevity. Across species, WD has been found to vary with phylogeny, moisture, temperature and xylem anatomy (e.g. vessel diameter). However, we know little abou...

Worldwide drought events causing tree growth decline and mortality are altering the carbon (C) balance of forest ecosystems. One unexplored aspect of trees’ vulnerability is whether responses to drought may be linked to species’ niche breadth. Using the most severe 2015-2016 El Niño drought event in the last 70 years in Patagonia, we determined pre...

Key message: At the sixth and seventh years of a drought event in south of Chile, non-structural carbohydrate (NSC) concentrations were similar between healthy and unhealthy trees of Araucaria araucana (Molina) K. Koch, and growth did not decrease, suggesting that leaf loss prevented C shortage in unhealthy trees. Context: Tree drought resistance a...

In alpine plants, the temporal variation in the concentrations of non-structural carbohydrates (NSC) is closely related to the growth phenology, which is largely controlled by annual variations in temperature. However, in alpine areas of Mediterranean-type climate regions, plants growing at low elevations are also exposed to seasonal drought. Given...

The dependence of trees on carbon and nutrient storage is critical to predicting the forest vulnerability under climate change, but whether evergreen and deciduous species differ in their use and allocation of stored resources during spring phenology is unclear. Using a high temporal resolution, we evaluated the role of spring phenology and shoot g...

Worldwide drought events have been reported to cause tree growth decline and mortality, thus altering the carbon (C) balance of forest ecosystems. While most of the attention has been focused on the physiological mechanisms associated with drought‐induced tree responses of a few species at specific locations, the ecological attributes of these spec...

Drought can alter leaf senescence and nutrient resorption, but whether these alterations are consistent between trees of contrasting leaf habits remains unclear. We conducted an experiment for 2 years with potted saplings to compare leaf habit and drought effects on leaf abscission dynamics and nutrient resorption proficiency in two evergreen and t...

It is unclear whether the frequently observed increase in non-structural carbohydrates (NSC) in plants exposed to low temperatures or drought reflects a higher sensitivity of growth than photosynthesis in such conditions (i.e. sink limitation), or a prioritization of carbon (C) allocation to storage. Alpine areas in Mediterranean-type climate regio...

Non-structural carbohydrates (NSC) are crucial for forest resilience, but little is known regarding the role of bark in NSC storage. However, bark's abundance in woody stems and its large living fraction make it potentially key for NSC storage. We quantified total NSC, soluble sugar (SS) and starch concentrations in the most living region of bark (...

There is an ongoing debate on whether a drought induced carbohydrate limitation (source limitation) or a direct effect of water shortage (sink limitation) limit growth under drought. In this study, we investigated the effects of the two driest summers recorded in southern Chile in the last seven decades, on the growth and non-structural carbohydrat...

Key message Non-structural carbohydrates (NSC) are the main form of carbon storage in broadleaved trees; precise NSC quantification is relevant to predict forest resilience. Sample microwaving before drying is considered to reduce NSC losses; however, evidence is scarce. We demonstrate that microwaving leaf and branch sapwood samples before drying...

Temperate trees rely on carbon (C) and nutrient remobilization from storage to resume growth after winter. Minimum storage levels during the growing season suggest that remobilization could signify that C availability is insufficient to meet growth demands; consequently, growth might be C and/or nutrient limited. However, it remains unclear whether...

Purpose of Review Nonstructural carbohydrates (NSC) promote tree survival when photosynthesis is impeded by factors whose impact is expected to increase under climate change, like droughts, herbivory, and fires. Nonetheless, it remains unclear whether NSC are depleted under natural conditions and if they mediate tree recovery. To determine if there...

The magnitude and frequency of insect outbreaks are predicted to increase in forests, but how trees cope with severe outbreak defoliation is not yet fully understood. Winter deciduous trees often produce a secondary leaf flush in response to defoliation (i.e., compensatory leaf regrowth or refoliation), which promotes fast replenishment of carbon (...

Background and aims: Cluster roots (CRs) constitute a special root adaptation that enables plants to take up nutrients, especially phosphorus (P), from soils with low nutrient availability, including recent volcanic deposits. It is unclear, however, how CR species interact with non-cluster root (NCR) species, and how substrates' fertility modulate...

Aims Southern South American Proteaceae can occupy soils that are rich in total phosphorus (P) but poor in available P (for example volcanic soils) thanks to their cluster roots (CR), which mine soil P. However, some southern South American Proteaceae occur in a wide range of soil nutrition. We hypothesized that CR formation and function are more r...

Premise: Two fundamental hypotheses on herbivore resistance and leaf habit are the resource availability hypothesis (RAH) and the carbon-nutrient balance hypothesis (CNBH). The RAH predicts higher constitutive resistance by evergreens, and the CNBH predicts higher induced resistance by deciduous species. Although support for these hypotheses is mi...

Several plant species have the potential to facilitate the presence of other plant species in the community, and yet most of our knowledge on this phenomenon comes from studies considering only one facilitator species. What happens when there are two facilitator species in the community? Are the facilitation effects by one species being altered by...

Premise of the study: It is unclear to what extent the co-occurrence of angiosperm and gymnosperm species in some marginal ecosystems is explained by reduced growth in angiosperms due to carbon (C) limitation and by high stress tolerance in gymnosperms associated with lack of vessels and resource conservation. Methods: We examined growth pattern...

Deep shade and waterlogging are two common stressors affecting seedling performance in the understorey of evergreen rainforests. It has been hypothesised that high levels of carbon storage confer shade- and waterlogging tolerances by preventing carbon limitation under such stresses. Whether the tolerance to both stresses is positively or negatively...

Insect herbivory is thought to favour carbon allocation to storage in juveniles of shade-tolerant trees. This argument assumes that insect herbivory in the understorey is sufficiently intense as to select for storage; however, understoreys might be less attractive to insect herbivores than canopy gaps, because of low resource availability and – at...

Widespread tree mortality associated with drought has been observed on all forested continents and global change is expected to exacerbate vegetation vulnerability. Forest mortality has implications for future biosphere-atmosphere interactions of carbon, water and energy balance, and is poorly represented in dynamic vegetation models. Reducing unce...

Since growth is more sensitive to drought than photosynthesis, trees inhabiting dry regions are expected to exhibit higher carbohydrate storage and less growth than their conspecifics from more humid regions. However, the same pattern can be the result of different genotypes inhabiting contrasting humidity conditions. To test if reduced growth and...

Premise of the study: A prevailing hypothesis in forest succession is that shade-tolerant species grow more slowly than shade-intolerant species, across light conditions, because they prioritize carbon (C) allocation to storage. We examined this hypothesis in a confamilial pair of species, including one of the fastest-growing tree species in the w...

Widespread tree mortality associated with drought has been observed on all forested continents and global change is expected to exacerbate vegetation vulnerability. Forest mortality has implications for future biosphere–atmosphere interactions of carbon, water and energy balance, and is poorly represented in dynamic vegetation models. Reducing unce...

Although the principal mechanism determining tree line formation appears to be carbon (C)‐sink limitations due to low temperatures, few studies have assessed the complementary role of reduced soil nutrient availability with elevation. We tested the hypothesis that nutrient (especially nitrogen, N) limitations at tree line may directly (via C‐source...

Plants store large amounts of non-structural carbohydrates (NSC). While multiple functions of NSC have long been recognized, the interpretation of NSC seasonal dynamics is often based on the idea that stored NSC is a reservoir of carbon that fluctuates depending on the balance between supply via photosynthesis and demand for growth and respiration...

The transition from seedlings into trees at alpine tree lines is a temperature‐limited process that ultimately sets the tree line elevation at a global scale. As such, tree lines may be key bioassays of global warming effects on species distributions. For global warming to promote upward tree line migration, as predicted, seedlings must be availabl...

Carbon (C) storage is considered a key component to plant survival under drought and shade, although the combined effects of these factors on survival remain poorly understood. We investigated how drought and shade alter the C dynamics and survival of tree seedlings, and whether drought limits the access to or usage of stored C. We experimentally a...

The growth limitation hypothesis ( GLH ) is the most accepted explanation for treeline formation, but it has been scarcely examined in Mediterranean regions, where treelines are located at lower elevations than in temperate regions. The GLH states that low temperature is the ultimate environmental driver for treeline formation, constraining C ‐sink...

Non-structural carbohydrates (NSC) in plant tissue are frequently quantified to make inferences about plant responses to environmental conditions. Laboratories publishing estimates of NSC of woody plants use many different methods to evaluate NSC. We asked whether NSC estimates in the recent literature could be quantitatively compared among studies...

Premise of the study: Carbon (C) allocation to storage in woody tissues at the expense of growth is thought to promote shade tolerance, yet few studies on the subject examined C storage during maximum growth and considered stand influences. I asked how C storage in different plant tissues relates to shade tolerance in temperate forests with contra...

Background and aims: There is a growing concern about how forests will respond to increased herbivory associated with climate change. Carbon (C) and nitrogen (N) limitation are hypothesized to cause decreasing growth after defoliation, and eventually mortality. This study examines the effects of a natural and massive defoliation by an insect on ma...

• Southern South American (SA) Proteaceae species growing in volcanic soils have been proposed as potential ecosystem engineers by tapping phosphorus (P) from soil through their cluster roots and shedding nutrient-rich litter to the soil, making it available for other species. We tested whether Embothrium coccineum (Proteaceae) has effectively lowe...

Background/Question/Methods Herbivory is an important constraint for seedling survival in shade, because low-light availability impedes a fast leaf reposition (i.e. re-foliation) after herbivory damage. It is thought that the difficulty in recovering from biotic or abiotic defoliation in low-light environments, and the low opportunity cost of sto...

Background/Question/Methods Forests store significant amounts of C globally. Evidence points to increasing climate-change induced drought as a primary driver of recent tree and forest mortality, thus generating an urgent need to predict how forests will cope with increasing stress. Although plants store non-structural carbon (NSC) to buffer again...

An innovative hypothesis to explain the higher carbon (C) and nitrogen (N) storage in woody tissues of winter deciduous species as compared to evergreen species is that these storages reflect an adaptation to tolerate herbivory. Support for this hypothesis has been little when manipulative defoliations were partial and/or applied in a single season...

The growth limitation hypothesis (GLH) is the most accepted mechanistic explanation for treeline formation, although it is still uncertain whether it applies across taxa. The successful establishment of Pinus contorta--an exotic conifer species in the southern hemisphere--above the Nothofagus treeline in New Zealand may suggest a different mechanis...

Cluster roots are a characteristic root adaptation of Proteaceae species. In South African and Australian species, cluster roots promote phosphorus (P) acquisition from poor soils. In a South American Proteaceae species, where cluster roots have been scarcely studied and their function is unknown, we tested whether cluster-root formation is stimula...

Background and Aims The most plausible explanation for treeline formation so far is provided by the growth limitation hypothesis (GLH), which proposes that carbon sinks are more restricted by low temperatures than by carbon sources. Evidence supporting the GLH has been strong in evergreen, but less and weaker in deciduous treeline species. Here a t...

For tropical lowland rain forests, Denslow (1987) hypothesized that in areas with large-scale disturbances tree species with a high demand for light make up a larger proportion of the flora; results of tests have been inconsistent. There has been no test for warm temperate rain forests (WTRFs), but they offer a promising testing ground because they...

Cluster roots (CR) of Proteaceae improve P acquisition through carboxilates exudation in old impoverish soils. Embothrium coccineum and Orites myrtoidea are two South American Proteaceae species that grow on volcanic depositions and in young rocky soils in the Andes. Because (P) starvation is the key factor inducing cluster-root formation in other...

Background/Question/Methods The classical view of deciduous tree species having higher dependence on carbon reserves for spring leaf-out and growth than evergreen species has been challenged lately; just a small proportion of carbon reserves in deciduous trees is indeed used during the leaf-out period. Thus, an unsolved and relevant ecological qu...

In low temperature-adapted plants, including treeline trees, light-saturated photosynthesis is considerably less sensitive to temperature than growth. As a consequence, all plants tested so far show increased nonstructural carbohydrate (NSC) tissue concentrations when exposed to low temperatures. Reduced carbon supply is thus an unlikely cause for...

Futuros escenarios climáticos limitarían el establecimiento de plántulas en bosques de los Andes del sur debido al estrés hídrico. Comparamos la resistencia a la sequía de plántulas de Nothofagus antarctica de dos límites arbóreos: Termas de Chillán (clima mediterráneo) y Antillanca (clima superhúmedo). También comparamos la resistencia a la sequía...

Futuros escenarios climáticos limitarían el establecimiento de plántulas en bosques de los Andes del sur debido al estrés hídrico. Comparamos la resistencia a la sequía de plántulas de Nothofagus antarctica de dos límites arbóreos: Termas de Chillán (clima mediterráneo) y Antillanca (clima superhúmedo). También comparamos la resistencia a la sequía...

A long-running debate centres on whether shade tolerance of tree seedlings is mainly a function of traits maximizing net carbon gain in low light, or of traits minimizing carbon loss. To test these alternatives, leaf display, light-interception efficiency, and simulated net daily carbon gain of juvenile temperate evergreens of differing shade toler...

Trees universally decrease their growth with age. Most explanations for this trend so far support the hypothesis that carbon (C) gain becomes limited with age; though very few studies have directly assessed the relative reductions of C gain and C demand with tree age. It has also been suggested that drought enhances the effect of C gain limitation...

• Introduction One current explanation for worldwide drought-induced tree mortality states that reduced photosynthesis and continued respiration lead to carbon depletion and eventually to carbon starvation. • Methods To determine if variations in gas exchange are consistent with variations in carbon storage, and if such consistency may depend on t...

Aim Two alternative hypotheses attempt to explain the upper elevation limit of tree lines world-wide, the carbon-limitation hypothesis (CLH) and the growth-limitation hypothesis (GLH); the altitudinal decrease of temperature is considered the driver constraining either carbon gain or growth. Using a widely distributed tree line species (Nothofagus...

• The focus of the trait-based approach to study community ecology has mostly been on trait comparisons at the interspecific level. Here we quantified intraspecific variation and covariation of leaf mass per area (LMA) and wood density (WD) in monospecific forests of the widespread tree species Nothofagus pumilio to determine its magnitude and whet...

The reduction of photosynthetic rates with tree age has been proposed as a major driver of the productivity declination along ontogeny. It is not clear, however, how environmental humidity affects stomatal conductance and biochemical potential of photosynthesis in trees belonging to different age-classes. We assessed daily cycles of gas exchange on...

A number of traits have been attributed important roles in tolerance of shade by plants. Some explanations emphasize traits enhancing net carbon gain; others emphasize energy conservation traits such as storage of non-structural carbohydrates (NSC). To date, cross-species studies have provided mixed support for the role of NSC storage in low-light...

The effects of gradual waterlogging on trees have been little studied. The températe evergreens Nothofagus nítida and N. dombeyi are differentially distributed on soil moisture gradients, only the former being common on poorly-drained sites. We compared the relative height growth rate (RGRH) and foliage loss of seedlings subjected experimentally to...

The effects of gradual waterlogging on trees have been little studied. The températe evergreens Nothofagus nítida and N. dombeyi are differentially distributed on soil moisture gradients, only the former being common on poorly-drained sites. We compared the relative height growth rate (RGRH) and foliage loss of seedlings subjected experimentally to...

Although tissue NSC concentrations did not conform to the adaptive pattern hypothesized by Kobe (1997), partitioning of the NSC pool between leaves, stems and roots of small seedlings did show an interesting relationship with species’ shade tolerance. Small seedlings of intolerant and mid-tolerant species had, on average, about half their NSC pool...

We asked if differences in distribution between Nothofagus nitida and N. dombeyi were associated with differences in drought tolerance. Survival, gas exchange and chlorophyll fluorescence were measured on seedlings subjected to a gradual drought. At a predawn leaf water potential (Ψm) of −2.7 MPa, survival of N. nitida was 50%, compared to 100% in...

The decrease in temperature with increasing elevation may determine the altitudinal tree distribution in different ways: affecting survival through freezing temperatures, by a negative carbon balance produced by lower photosynthetic rates, or by limiting growth activity. Here we assessed the relative importance of these direct and indirect effects...

Nothofagus dombeyi (Mirb.) Blume and Nothofagus nitida (Phil.) Krasser are closely related evergreen trees native to south central Chile. Nothofagus dombeyi is a pioneer in habitats subject to high daytime irradiances and nighttime freezing temperatures and has a wider altitudinal and latitudinal distribution than N. nitida, which is restricted to...

Se determinó la ingestión de nutrientes en Panicam coloraturn L., a cuatro niveles de oferta de forraje (OF) (15, 30, 45 y 60 g de MS - kg. PV ' - día-'). Se emplearon seis ovinos por tratamiento durante un período de me-dición de ocho días. La cantidad de forraje en prepastoreo (Fpre) se estimó a partir de cortes a nivel del suelo y la cantidad re...