Effect of the light environment on seed germination of red alder (Alnusrubra)

1993 ◽  
Vol 23 (7) ◽  
pp. 1487-1491 ◽  
Author(s):  
Sybille Haeussler ◽  
John C. Tappeiner II
Keyword(s):  
Leaf Litter ◽  
Red Light ◽  
Mineral Soil ◽  
Field Studies ◽  
Douglas Fir ◽  
Understory Vegetation ◽  
Light Conditions ◽  
Complete Darkness ◽  
Red Alder ◽  
Disturbed Habitats

Red alder (Alnusrubra Bong.) seed showing strong phytochrome activity in the laboratory was tested to determine whether the phytochrome effect could influence germination under light conditions experienced in the field. Seeds in sealed Petri dishes were placed beneath three types of overstory cover (clearcut (no overstory); Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) (coniferous evergreen overstory); and red alder (broad-leaved deciduous overstory)) and seven types of understory cover (control (complete darkness); uncovered; 1-cm mineral soil; leaf litter; moss; swordfern; and non-evergreen herbs). Germination was highest in clearcuts (68.6%), intermediate in Douglas-fir stands (47.4%), and lowest in red alder stands (11.7%). Covers of understory vegetation, leaf litter, and mineral soil significantly reduced germination, with the greatest reduction occurring where understory vegetation was dense enough to significantly reduce the ratio of red:far-red light. These findings concur with field studies of red alder seedling establishment and suggest that the phytochrome sensitivity of red alder seed plays an important role in this species' success on disturbed habitats.

scholarly journals Mineralisation, leaching and stabilisation of <sup>13</sup>C-labelled leaf and twig litter in a beech forest soil

2011 ◽  
Vol 8 (8) ◽  
pp. 2195-2208 ◽  
Author(s):  
A. Kammer ◽  
F. Hagedorn
Keyword(s):  
Leaf Litter ◽  
Mineral Soil ◽  
Soil Surface ◽  
Field Studies ◽  
Beech Forest ◽  
Organic C ◽  
Soil C ◽  
C Storage ◽  
Swiss Jura ◽  
C Mineralisation

Abstract. Very few field studies have quantified the different pathways of C loss from decomposing litter even though the partitioning of C fluxes is essential to understand soil C dynamics. Using 0.75 kg m−2 of 13C-depleted leaf (δ13C = −40.8 ‰) and 2 kg m−2 of twig litter (δ13C = −38.4 ‰), we tracked the litter-derived C in soil CO2 effluxes, dissolved organic C (DOC), and soil organic matter of a beech forest in the Swiss Jura. Autotrophic respiration was reduced by trenching. Our results show that mineralisation was the main pathway of C loss from decomposing litter over 1 yr, amounting to 24 and 31 % of the added twig and leaf litter. Contrary to our expectations, the leaf litter C was mineralised only slightly (1.2 times) more rapidly than the twig litter C. The leaching of DOC from twigs amounted to half of that from leaves throughout the experiment (2 vs. 4 % of added litter C). Tracing the litter-derived DOC in the soil showed that DOC from both litter types was mostly removed (88–96 %) with passage through the top centimetres of the mineral soil (0–5 cm) where it might have been stabilised. In the soil organic C at 0–2 cm depth, we indeed recovered 4 % of the initial twig C and 8 % of the leaf C after 1 yr. Much of the 13C-depleted litter remained on the soil surface throughout the experiment: 60 % of the twig litter C and 25 % of the leaf litter C. From the gap in the 13C-mass balance based on C mineralisation, DOC leaching, C input into top soils, and remaining litter, we inferred that another 30 % of the leaf C but only 10 % of twig C could have been transported via soil fauna to soil depths below 2 cm. In summary, over 1 yr, twig litter was mineralised more rapidly relative to leaf litter than expected, and much less of the twig-derived C was transported to the mineral soil than of the leaf-derived C. Both findings provide some evidence that twig litter could contribute less to the C storage in these base-rich forest soils than leaf litter.

scholarly journals Effects of soil acidity on Douglas fir seedlings. 1. Rooting characteristics of natural regeneration of Douglas fir in strongly acid forest soils.

1987 ◽  
Vol 35 (4) ◽  
pp. 533-536
Author(s):  
H.P. Smit ◽  
N. van Breemen ◽  
W.G. Keltjens
Keyword(s):  
Pseudotsuga Menziesii ◽  
Natural Regeneration ◽  
Soil Acidity ◽  
Mineral Soil ◽  
Field Studies ◽  
Douglas Fir ◽  
Total Root Length ◽  
Exchangeable Ca ◽  
Exchangeable Al ◽  
Acid Forest Soils

Results of field studies suggested that total root length of Douglas fir (Pseudotsuga menziesii) in mineral soil was affected by high exchangeable Al accompanied by low exchangeable Ca. This was only true, however, if the mineral soil to 5 cm depth was extremely acid (pH

Water chemistry profiles in an early- and a mid-successional forest in coastal British Columbia

1982 ◽  
Vol 12 (2) ◽  
pp. 240-248 ◽  
Author(s):  
Dan Binkley ◽  
J. P. Kimmins ◽  
M. C. Feller
Keyword(s):  
Water Chemistry ◽  
Forest Ecosystem ◽  
Stream Water ◽  
Mineral Soil ◽  
Douglas Fir ◽  
Mineral Weathering ◽  
Nutrient Concentrations ◽  
Saturated Zone ◽  
Red Alder ◽  
Zone Water

Water chemistry profiles of an 18-year-old forest ecosystem are compared with those of a 70- to 90-year-old forest ecosystem for a 9-month period. The younger ecosystem was dominated by Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and red alder (Alnusrubra Bong.) whereas western hemlock (Tsugaheterophylla (Raf.) Sarg.), Douglas-fir, and western red cedar (Thujaplicata Donn.) dominated the older ecosystem. Concentrations of nutrients and other chemicals were measured in throughfall, forest floor and mineral soil lecachates, saturated-zone water, and stream water. Concentrations of dissolved chemicals were much greater in the younger ecosystem than in the older ecosystem at intermediate stages in the profiles. However, stream water concentrations differed less between the two ecosystems for most of the chemicals investigated. Nitrate and silica were exceptional; stream water nitrate concentrations in the younger ecosystem averaged 16 times greater than those in the older ecosystem. This was probably a result of biological nitrogen fixation by red alder in the younger ecosystem, a process which would more than compensate for the higher nitrate losses. Silica concentrations in the younger ecosystem consistently exceeded levels in the older ecosystem by 40 to 100%. suggesting a possibility of a greater rate of mineral weathering in the younger ecosystem.Although nutrient concentrations were higher in the soil leachates of the younger ecosystem, these higher levels failed to persist through the saturated-zone water and stream water stages of the water chemistry profile. Consequently, the younger ecosystem appeared relatively more efficient at retaining dissolved nutrients than the older ecosystem. Stream water chemistry was relatively insensitive to the magnitudes of the differences in biogeochemical process rates of the two ecosystems.

scholarly journals Mineralisation, leaching and stabilisation of <sup>13</sup>C-labelled leaf and twig litter in a beech forest soil

2011 ◽  
Vol 8 (1) ◽  
pp. 1043-1076
Author(s):  
A. Kammer ◽  
F. Hagedorn
Keyword(s):  
Leaf Litter ◽  
Mineral Soil ◽  
Soil Surface ◽  
Field Studies ◽  
Beech Forest ◽  
Organic C ◽  
C Storage ◽  
C Stocks ◽  
Mineral Soils ◽  
One Year

Abstract. Very few field studies have quantified the different pathways of C loss from decomposing litter even though this is essential to better understand long-term dynamics of C stocks in soils. Using 13C-labelled leaf (isotope ratio (δ13C) = −40.8‰) and twig litter (δ13C = −38.4‰), we tracked down the litter-derived C in the soil respiration, in the dissolved organic C (DOC) and in the soil organic matter of a beech forest in the Swiss Jura. After one year of decomposition, mass loss in the litter layer was almost twice as great for leaves as it was for twigs (75% vs. 40%). This difference was not the result of a slow mineralisation of the woody litter, but primarily of the only slight incorporation of twig-derived C into mineral soils. The C mineralisation rates of the twig litter were only slightly lower than those of the leaf litter (10–35%), in particular after the loss of the readily available litter fraction. However, the leaching of DOC from twigs amounted only to half of that from leaves. Tracing the litter-derived DOC showed that DOC from both litter types was mostly retained (88–96%) and stabilised in the top centimetres of the mineral soil. In the soil organic C at 0–2 cm depth, we recovered 8% of the initial leaf C, but only 4% of the twig C. Moreover, the 13C mass balance suggested that a substantial fraction of the leaf material (~30%) was transported via soil fauna to soil depths below 2 cm, while the twig litter mainly decomposed in situ on the soil surface, probably due to its rigid structure and low nutritional value. In summary, our study shows that decaying twigs are rapidly mineralised, but seem to be clearly less important for the C storage in this beech forest soils than leaf litter.

Cation distribution, cycling, and removal from mineral soil in Douglas-fir and red alder forests

1992 ◽  
Vol 16 (2) ◽  
pp. 121-150 ◽  
Author(s):  
Peter S. Homann ◽  
Helga van Miegroet ◽  
Dale W. Cole ◽  
Gordon V. Wolfe
Keyword(s):  
Cation Distribution ◽  
Mineral Soil ◽  
Douglas Fir ◽  
Red Alder

Biological invasions: are they dependent on disturbance?

1997 ◽  
Vol 5 (2) ◽  
pp. 131-144 ◽  
Author(s):  
J D Lozon ◽  
H J MacIsaac
Keyword(s):  
Exotic Species ◽  
Human Activities ◽  
Water Discharge ◽  
A Priori ◽  
Terrestrial Ecosystems ◽  
Field Studies ◽  
Soil Disturbance ◽  
Exotic Animals ◽  
Introduced Plants ◽  
Disturbed Habitats

We utilize literature surveys to examine the relationship between establishment of exotic species and human or natural disturbances of ecosystems. Of the 133 papers published in 10 ecological journals between 1993 and 1995, 63 reported on field studies involving 299 and 103 successful, nonredundant plant and animal introductions, respectively. Invasions of terrestrial ecosystems dominated (>>97%) the surveyed literature. Disturbance was associated with establishment of exotic species in 56% of these studies, though its importance differed among papers describing plants (68%) and animals (28%). Plants species (86%) were significantly more dependent on disturbance for establishment than were animals (12%). However, animals and plants that were dependent on disturbance for establishment were almost equally dependent (58 versus 68%) on it for range expansion. In a second survey, 402 plant and 103 animal taxa were identified that explicitly linked establishment of exotic species to disturbance. Human activities were attributed with establishment of species in 97 and 57% of these cases, respectively. Common mechanisms associated with establishment of exotic animals included ballast water discharge, intentional releases, and residential development. Establishment of exotic plants was associated with animal activities (e.g., grazing, seed introduction), soil disturbance, forestry, fire, agriculture, and human activities. In contrast to invasions theory, our survey indicates that the association between establishment and spread of exotic species and disturbance ought not be assumed a priori. Some animals repeatedly invade new habitats once geographic barriers are circumvented, indicating that communities may be more receptive to exotic species than previously acknowledged. By contrast, introduced plants established most often in disturbed habitats.

scholarly journals A PHYSIOLOGICAL APPROACH TO CONSERVATION OF FOUR PALM SPECIES: ARENGA AUSTRALASICA, CALAMUS AUSTRALIS, HYDRI- ASTELE WENDLANDIANA AND LICUALA RAMSAYI

REINWARDTIA ◽  
2014 ◽  
Vol 14 (1) ◽  
pp. 237
Author(s):  
Dian Latifah ◽  
Robert A. Congdon ◽  
Joseph A. Holtum
Keyword(s):  
Economic Value ◽  
Red Light ◽  
Tropical Rainforests ◽  
Light Conditions ◽  
Marginal Lands ◽  
Hard Seed ◽  
Palm Species ◽  
Physiological Approach ◽  
Physical Treatments ◽  
Seed Coats

Palms (Arecaceae) are an important component of many tropical rainforests. Many have also been cultivated widely for agricultural commodities with high economic value. They are also important components in rehabilitation of disturbed or marginal lands. Knowledge and application of germination strategies are essential in the cultivation of palms. Many species have seeds that do not germinate readily, even when light conditions are favourable. This research determined the effects of seed coats, light and temperature on germination of Arenga australasica (H. Wendl. & Drude) S. T. Blake ex H. E. Moore, Calamus australis Mart., Hydriastele wendlandiana (F. Muell.) H. Wendl. & Drude and Licuala ramsayi var. tuckeri Barford & Dowe. We examined physical treatments to promote germination or break dormancy, as well as different light and temperature conditions. The results showed that the hard seed coats of the four species slowed imbibition. Scarified seeds germinated best for A. australasica, C. australis and L. ramsayi. The germination of all seeds was inhibited by far red light. The red light requirement suggests that these species prefer to colonise open areas. This implies that dispersal agents, canopy gaps and forest margins may play important roles in promoting regeneration as well as conservation of these palm species.

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