Twenty-three years of stand dynamics in an old-growth Chamaecyparis forest in central Japan

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  • ORIGINAL ARTICLE

    Twenty-three years of stand dynamics in an old-growthChamaecyparis forest in central Japan

    Michinari Matsushita Daisuke Hoshino

    Shin-Ichi Yamamoto Naoyuki Nishimura

    Received: 25 June 2012 / Accepted: 26 January 2013 / Published online: 6 March 2013

    The Japanese Forest Society and Springer Japan 2013

    Abstract Structures and dynamics of old-growth conif-

    erous stands are affected by several types of disturbances

    including typhoons. We report the forest dynamics of four

    old-growth Chamaecyparis stands in central Japan that

    differ in the disturbance history of typhoons over a period

    of 23 years. The stem number, basal area and mortality

    were examined. In a predominant stand of C. obtusa (Sieb.

    et Zucc.) Endl., 24 % of the C. obtusa canopy trees died,

    mainly as a result of the severe damage of a strong typhoon

    that caused a single tree-fall gap and the following gap

    enlargements. In this stand, the total basal area decreased to

    76.5 % of the initial value, although the mortality declined

    in recent years. In contrast, the other three stands decreased

    only slightly in the stem numbers (0.05.6 %) and

    increased in the basal areas of C. obtusa canopy trees. It is

    confirmed that the stand-level ingrowths of 300-year-old

    C. obtusa canopy trees could contribute to the increase in

    the stock of each stand. Our results support an idea that the

    dynamics of old-growth Chamaecyparis forests were

    greatly affected by typhoons. The stand structures will be

    gradually changed (with the processes of gap dynamics)

    and C. obtusa will continue to be dominant, potentially

    over hundreds of years.

    Keywords Forest dynamics Gap formation Long-term study Natural disturbance Stem growth

    Introduction

    Stand structures and dynamics are often affected by several

    types of disturbances (e.g., typhoons) that vary in intensity

    and frequency (Yamamoto et al. 2011; Torimaru et al.

    2012). In many old-growth coniferous forests in East Asia,

    gap creation by typhoons is one of the major disturbance

    regimes (e.g., Asai et al. 2003). Because such disturbances

    occur infrequently and stochastically (Yamamoto et al.

    2011; Torimaru et al. 2012), their effects on dynamics of

    old-growth forests are often complex (Parish and Antos

    2004), and therefore long-term monitoring studies are

    important.

    The genus Chamaecyparis is distributed around the

    Pacific basin and along the eastern coast of North America

    (Farjon 2005). Most Chamaecyparis species are known as

    long-lived with slow growth rates. For example, the max-

    imum age of C. formosensis, a species in Taiwan, exceeds

    ca. 3,000 years old (Zobel 1998). In North America,

    C. nootkatensis is a very long-lived stress tolerator found in

    a wide variety of habitats, which appears to need some

    opening of the stand to reach the canopy (Antos and Zobel

    1986; Antos et al. 2005; Parish and Antos 2006). Because

    Nomenclature: Ohwi and Kitagawa (1992).

    M. Matsushita (&)Laboratory of Forest Sciences, Department of Biological

    Environment, Akita Prefectural University, Akita 010-0195,

    Japan

    e-mail: mats.m.michi@gmail.com

    D. Hoshino

    Tohoku Research Center, Forestry and Forest Products Research

    Institute, 92-25, Morioka, Iwate 020-0123, Japan

    S.-I. Yamamoto

    Laboratory of Forest Plant Ecology, Graduate School

    of Bioagricultural Sciences, Nagoya University, Chikusa,

    Nagoya 464-8601, Japan

    N. Nishimura

    Environmental Sciences Laboratory, Faculty of Social

    and Information Studies, Gunma University, 4-2 Aramaki,

    Maebashi, Gunma 371-8510, Japan

    123

    J For Res (2014) 19:134142

    DOI 10.1007/s10310-013-0398-x

  • of their longevities and slow growth, the regeneration

    processes of Chamaecyparis species have not fully been

    understood.

    Two Chamaecyparis species, C. obtusa (Sieb. et Zucc.)

    Endl. and C. pisifera (Sieb. et Zucc.) Endl. are indigenous

    to Japan. The rates of exploitation of Chamaecyparis have

    been very high in the past, since the lumber of Chamae-

    cyparis spp., especially C. obtusa, has been used prefer-

    entially to build feudal architectures (e.g., castles) because

    of its excellent quality (Nishioka and Obara 1975; Ito

    2000). According to IUCN 2010, C. obtusa is classified as

    Near Threatened, and the remaining natural C. obtusa

    forests are small and fragmented (Maeda 1951; Maeda and

    Yoshioka 1952; Matsumoto et al. 2010). Therefore, their

    conservation has been an important and urgent issue

    (Yamamoto 1998; Tsumura et al. 2007). Currently, Kiso

    district in central Japan is the core habitat over the entire

    geographical distribution of natural C. obtusa populations

    (Matsumoto et al. 2010); old-growth Chamaecyparis for-

    ests are rare and thus very precious because of both

    their ecological and commercial value (Yokouchi 1970;

    Yamamoto 1998).

    Akaswa Forest Reserve in the Kiso district is an excel-

    lent representative of Chamaecyparis forests, characterized

    by the pronounced dominance of C. obtusa (Nagano

    Regional Forest Office 1985; Yamamoto 1993a; Hoshino

    et al. 2001). Most Chamaecyparis canopy trees reach

    around 300 years old (Hoshino et al. 2001; Asai et al.

    2003). To understand the current condition and long-term

    trends in Chamaecyparis forests, we began to examine the

    dynamics of typical old-growth stands in this Reserve in

    1985. In this paper, we report the dynamics of old-growth

    C. obtusa stands over 23 years: i.e., the changes in the stem

    number, basal area and mortality patterns. Since little

    information is available on old-growth Chamaecyparis

    forests, our report provides useful information about Cha-

    maecyparis regeneration.

    Here, specific questions were: (1) are the number and

    basal area of C. obtusa canopy trees decreasing or

    increasing; (2) how much are C. obtusa trees growing in

    diameter; and (3) what, if any, are the mortality patterns of

    C. obtusa trees? We summarized the structure and

    dynamics of each stand focusing on the role of typhoon

    disturbances, and then discussed long-term trends and

    future states of old-growth Chamaecyparis forests.

    Materials and methods

    Study area

    The Akasawa Forest Reserve (354305700N, 1373705000E;1,046 ha; 1,0801,558 m a.s.l.) is located in the Kiso

    district of Nagano Prefecture, central Honshu, Japan

    (Nagano Regional Forest Office 1985). Annual precipita-

    tion is ca. 2,500 mm and snow accumulation is 50100 cm.

    The mean annual temperature is 7.8 C at 1,113 m a.s.l.;the mean monthly maximum and minimum temperatures

    are 14.3 C in August and -11.8 C in February, respec-tively. The reserve is on an elevated peneplain with a

    gentle slope. The geology is dominated by acidic igneous

    rocks, including granite, granite porphyry and rhyolite.

    Soils are mainly dry or wet podzols, although brown forest

    soils appear on hillsides or along streams (Nagano Regio-

    nal Forest Office 1985; Yamamoto 1993a).

    Old-growth Chamaecyparis stands in this Reserve, like

    the other stands in the Kiso and neighboring districts, have

    become established after heavy cutting during 16881703

    (Nagano Regional Forest Office 1985). Since that time, most

    stands have been protected from heavy cutting, but selection

    cutting mainly for hardwoods has been undertaken.

    In the reserve, C. obtusa mainly dominates the over-

    story, and C. pisifera frequently co-dominates on the lower

    slopes or along the streams (Nagano Regional Forest Office

    1985; Hoshino et al. 2001). Other coniferous trees like

    Thujopsis dolabrata (L.f.) Sieb. et Zucc. and Thuja

    standishii (Gordon) Carrie`re, and some hardwood trees

    such as Magnolia obovata Thunb. and Quercus mongolica

    Fisch. ex Ledeb. var. grosseserrata (Blume) Rehder et

    E.H.Wilson, occasionally co-occur. The understory layer in

    this Reserve is characterized by dense cover of the saplings

    of T. dolabrata, occasionally with small trees of some

    broadleaved species (Yamamoto and Suto 1994; Hoshino

    et al. 2001, 2003; Matsushita et al. 2010). T. dolabrata is a

    highly shade-tolerant species which can reproduce by

    layering under closed canopy conditions (Yamamoto and

    Suto 1994); meanwhile, the seedlings of C. obtusa estab-

    lished on exposed mineral soil beneath tree-fall gaps

    (Yamamoto 1988, 1993b), and there are no or very few

    saplings of C. obtusa (Yamamoto and Suto 1994; Hoshino

    et al. 2001, 2003).

    Study plot and field methods

    Four representative old-growth stands were chosen for this

    study (Table 1). The canopy of Stand O consisted of only

    C. obtusa, whereas Stands S and H had a few other species

    in the canopy but were dominated by C. obtusa. However,

    several species co-existed in the canopy of Stand K. While

    there were no records of selection cutting in Stand H,

    Stands O, S and K underwent selection cutting during the

    period 19151947, mainly to remove dead canopy trees

    (Nagano Regional Forest Office 1985). When C. obtusa

    trees have died naturally (e.g., as the result of typhoons),

    the dead trees have been (but not frequently) removed from

    the reserve by forest managers.

    J For Res (2014) 19:134142 135

    123

  • There is no evidence of forest fires, but typhoons are a