Annual growth zones in stems of <i>Hypericum irazuense</i> (Guttiferae) in the Costa Rican páramos

Kerr, M.; Horn, Sally P.; Grissino-Mayer, Henri D.; Stachowiak, Lauren A.

doi:10.1080/02723646.2017.1340714

Cited by 4 publications

(5 citation statements)

References 26 publications

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“…The páramo ecosystem within Chirripó NP, which extends from ~3300 to 3819 m asl, is dominated by dwarf bamboo ( Chusquea subtessellata ). This dwarf bamboo species comprises approximately 60% of the vegetation cover and co-occurs with other evergreen shrubs (all <10% cover), such as Hypericum strictum , Hypericum irazuense , Vaccinium consanguineum , and Escallonia myrtillioides (Kappelle and Horn, 2016; Kerr et al, 2018). A diversity of tussock grasses, sedges, dicotyledonous herbs, prostrate shrubs, pteridophytes, and mosses grow beneath the shrub canopy and in more open areas (Horn, 1993).…”

Section: Study Areamentioning

confidence: 99%

A high-resolution sedimentary charcoal- and geochemistry-based reconstruction of late Holocene fire regimes in the páramo of Chirripό National Park, Costa Rica

Porinchu

2019

Quat. res.

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Multiproxy analysis of two sediment cores recovered from lagos Morrenas 3C and Ditkebi, located in the páramo of Costa Rica's Chirripó National Park, was undertaken to develop multidecadal-scale reconstructions of late Holocene fire regimes for the region. Analysis of macroscopic charcoal and sediment geochemistry (C%, N%, δ13C, δ15N, and C/N ratios) documents periodic burning of the páramo in Chirripó National Park during the past ~1700 yr. The charcoal records provide evidence of high fire frequency between AD ~560 and 720 and between AD ~980 and 1230. Severe fire episodes are reflected by a rapid increase in the flux of carbon (C) and nitrogen (N) from the surrounding catchment because of the volatilization of páramo vegetation. Additionally, δ15N, which sharply increases following local fire events, captures postfire changes in nutrient loading and, likely, the decadal-scale rate of postfire recovery of páramo vegetation. The consistently high δ13C and C/N values observed between AD ~700 and 1100 suggest an expansion of Muhlenbergia, a native C4 grass growing near shore, suggesting that the interval between AD ~700 and 1100, broadly corresponding to the Terminal Classic Drought and Medieval Climate Anomaly, was characterized by a decrease in effective moisture and temperature.

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Section: Study Areamentioning

confidence: 99%

A high-resolution sedimentary charcoal- and geochemistry-based reconstruction of late Holocene fire regimes in the páramo of Chirripό National Park, Costa Rica

Porinchu

2019

Quat. res.

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“…Previous dendrochronological studies have discovered annual rhythms in growth rings of trees and shrubs distributed around many different tropical ecosystems: from mangroves to the limit of woody vegetation at about 5000 m a.s.l. ; from woodland savannas to dry and flooded forests (Brienen et al, 2016; Franco‐Ramos et al, 2019; Kerr et al, 2018; Locosselli et al, 2020; Requena‐Rojas et al, 2021; Rodriguez‐Caton et al, 2021; Schöngart et al, 2017). Here we include new evidences of annual tree‐ring in the last unexplored frontier, the ever‐wet tropical forests.…”

Section: Discussionmentioning

confidence: 99%

Tree growth periodicity in the ever‐wet tropical forest of the Americas

et al. 2023

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The occurrence of annual growth rings in tropical trees—the result of the seasonal activity of vascular cambium—has been explained by seasonal water deficit or flooding periods. However, little is known about the drivers of annual tree‐ring formation under tropical hyper‐humid conditions without clear seasonal dry periods or flooding (ever‐wet conditions). Shelford's law states that the deficit or the excess of environmental resources limits plant growth. Accordingly, we hypothesize that excess soil moisture, a slight seasonal reduction of precipitation and a reduction in light availability determine rhythmic growth in ever‐wet tropical forests. We first assessed the occurrence of rhythmic growth in 14 tree species from the Biogeographic Chocó Region (annual rainfall 7200 mm) using three methods: Radiocarbon (14C) dating (all studied species), tree‐ring synchronization (4 species that have replicates) and automatic dendrometers (two species). Then, we assessed the effect of environmental drivers (rainfall, short‐wave radiation, temperature and soil moisture) on tree growth based on tree ring and dendrometer observations. We present evidence of annual tree‐ring formation in all 14 studied tree species. Depending on the tree species, we observed positive and negative correlations between growth, water availability and light availability. These relationships suggest that both excess or deficit of environmental resources may explain the seasonal pattern of tree growth. Although we cannot differentiate between excess soil water and low light availability by high cloudiness, we suggest that cloudiness frequency could affect tree growth in these forests. Synthesis. We reveal the annual formation of growth rings in the unexplored wetter‐end tropical forests, where seasonal growth depends on either high soil moisture and hypoxia or light limitations by cloudiness and photosynthesis constraints.

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“…It would be useful to have a field method of indicating time since fire in these regions also. Tussock grass development through time after fire has potential in this regard, but other indicators should also be considered such as growth rings or zones in shrubs (Kerr et al 2017).…”

Section: Discussionmentioning

confidence: 99%

“…The use of ecological indicators has been proposed as a possible approach to determine time since fire at a landscape scale in the páramo. In Costa Rican páramos, the growth rings of certain shrubs can be used to date fires (Horn 1989;Kerr et al 2017;Williamson et al 1986), but this approach is limited in the páramos of northern Ecuador because shrubs do not reliably form annual growth rings there (personal observation by authors). Garcia-Meneses and Ramsay (2014) investigated the use of Puya giant rosettes plants to estimate time since fire.…”

Section: Introductionmentioning

confidence: 99%

Espeletia giant rosette plants are reliable biological indicators of time since fire in Andean grasslands

Zomer

Ramsay

2017

Plant Ecol

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Páramo grasslands in the tropical Andes are fire prone ecosystems and an understanding of their fire ecology is fundamental to biodiversity conservation and ecosystem management. Fire registers are normally impractical in these remote, cloud-covered landscapes, but Espeletia giant rosette plants have been proposed as biological indicators of time since fire in páramos. Espeletia giant stem rosettes tolerate fire well, protecting apical buds in at the heart of their leaf rosettes, and for some species, germination is known to be enhanced by fire. As the plant grows, its dead leaves remain attached to the stem, but fire removes these and resets the "leaf clock". This study uses a unique register of fires in one Ecuadorian páramo to assess the robustness of this biological indicator. Dead leaf cover on Espeletia pycnophylla giant rosette plants was measured in fifteen different sites with known fire dates from 2000 to 2014. The growth rates of plants at four different elevations were measured over a two-year period and used to estimate time since fire based on dead leaf cover in the known sites. Estimates were accurate to ± 2 y. Thus, where fire records are missing, relatively easy measurements of growth rates and dead leaf cover of Espeletia giant rosette plants can provide reliable estimates across a wide range of times since fire. This approach has value for direct investigations into fire ecology but also for studies in which controlling for fire dynamics is necessary to reveal underlying patterns. Therefore, this approach also offers a means to obtain better information on other landscape-scale processes such as the impact of climate change on biodiversity or the provision of ecosystem services.

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Annual growth zones in stems of Hypericum irazuense (Guttiferae) in the Costa Rican páramos

Cited by 4 publications

References 26 publications

A high-resolution sedimentary charcoal- and geochemistry-based reconstruction of late Holocene fire regimes in the páramo of Chirripό National Park, Costa Rica

A high-resolution sedimentary charcoal- and geochemistry-based reconstruction of late Holocene fire regimes in the páramo of Chirripό National Park, Costa Rica

Tree growth periodicity in the ever‐wet tropical forest of the Americas

Espeletia giant rosette plants are reliable biological indicators of time since fire in Andean grasslands

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