About

I am the senior indigenous forests scientist at the Bioeconomy Science Institute (Scion Group), investigating challenges and opportunities for indigenous forestry in New Zealand. I lead innovative research and development into the physiological mechanisms driving growth and impacts of climate change in New Zealand’s native forests.

Since 2011, I have been investigating the long-term effects of different silvicultural regimes on the structure and dynamics of podocarp-broadleaved forests in New Zealand and compare past and present management on public land and Māori freehold land.

My collaboration includes national and international agencies such as other groups across the Bioeconomy Science Institute, research organisations, government departments (MPI, MfE, DOC, etc.), regional and local authorities, and universities. A particular key focus of my work is leading and advocating discussions and research opportunities related to indigenous forestry with Māori iwi and hapu.

Prior work includes project coordination for the Northwest German Forest Institute in Göttingen, investigating the impact of indigenous forestry on biodiversity on a landscape level. I have also been a Scientific Consultant for Sustainable Forest and Wildlife Management, working for over 25 years in many forest ecosystems around the world.

Over the past three decades, I have carried out numerous projects in many parts of the world, and I am passionate about using my experience and knowledge to the promotion and advance of indigenous forestry in NZ for the benefit of all New Zealanders.

Qualifications

M.Sc. Forest Sciences of Temperate Forests (1998)

M.Sc. Forest Sciences of Tropical and Subtropical Forests (2002)

PhD Forest Sciences (Indigenous Forestry and Forest Ecology) (2018)

Research capabilities

- Indigenous Forestry

- Silviculture

- Tree improvement (including selection and breeding)

- Applied forest ecology

- Forest biodiversity

- Forest Dynamics

- Plant development and physiology

- Agroforestry

- Ecosystem function

- Ecological impacts of climate change and ecological adaptation

- Landscape ecology

- Forest conservation

- Forest assessment and monitoring

- Natural resource management

- Environmental education

Career highlights

- Scientific Consultant for Sustainable Forest and Wildlife Management with over 25 years of international experience

- Project coordinator at the Northwest German Forest Research Institute in Göttingen, Germany

- Senior Indigenous Forests Scientist at the New Zealand Forest Research Institute (formerly Scion, now Bioeconomy Science Institute)

Selected papers

Salekin, S., Roschak, C., Steward, G. (2025): Development of a height-diameter model for New Zealand grown tōtara (Podocarpus totara G. Benn. ex. D. Don). New Zealand Journal of Forestry Science 55:11.

Keye, C., Schmidt, M., Roschak, C., Dorow, W. H. O., Hartung, V., Pauls, S. U., Schneider, A., Ammer, C., Zeller, L., & Meyer, P. (2024). Adaptive monitoring in action—what drives arthropod diversity and composition in central European beech forests? Environmental Monitoring and Assessment, 196(5), 470.

Zeller, L., Förster, A., Keye, C., Meyer, M., Roschak, C., Ammer, C. (2023). What does literature tell us about the relationship between forest structural attributes and species richness in temperate forests? – A review. Ecological Indicators 153, September 2023, 110383.

Peter Meyer, Eike Feldmann, Jonas Hagge, Constanze Keye, Katja Lorenz, Rouven Nagel, Andreas Moelder, Christian Roschak, Marcus Schmidt, Wolfgang Schmidt, David Singer, Laura Zeller. (2023). Fünf Jahrzehnte Naturwaldforschung in Niedersachsen. AFZ-DerWald(13), 14-18.

Roschak, C., Meyer, P., Schmidt, M., & Lorenz, K. (2021). Aufnahmeanweisung: Struktur- und Biotopkartierung der hessischen Naturwaldreservate aus tierökologischer Sicht. Northwest German Forest Research Institute. Goettingen. 28 pages.

Hagge J., Schmidt M., Ammer C., Dorow W., Keye C., Pauls S., Roschak C., Schneider A., Meyer P. (2021) Zielsetzungen und Anforderungen an ein bundesweites Insektenmonitoring in Wäldern. Naturschutz und Landschaftsplanung 53 (11): 10-13.

Roschak, C. (2017). Structure and dynamics of lowland podocarp-broadleaved forest in the Central North Island, New Zealand [Ph.D. thesis, University of Canterbury].

Keye, C., Roschak, C., Ross, J. (2011). Summer home range size and population density of great spotted kiwi (Apteryx hastii) in the North Branch of the Hurunui River, New Zealand. Notornis, Vol. 58:22-30

Roschak, C. und Meier, D. (2002). Black bears (Ursus americanus) and White-tailed deer (Odocoilus virginianus) at Rancho Santa Maria in Nuevo Leon, Mexico. Report on three months of Scientific Research from Sept. 23^rd until Dec. 15^th 2001. Cemex, 75 p.

Roschak, C. (2001). Geschichtliche Entwicklung der Korup Region im Südwesten Kameruns – Über die Notwendigkeit von Naturschutz. In: Freese, J., Appelfelder, J., Camphausen, A., Groth, Roschak, C., B., Fischer, B., 2001: Kamerun – Korup Nationalpark und Support Zone. Reihe: Internationale und interdisziplinäre Urwaldforschung, Zentrum für Naturschutz der Univ. Göttingen, 68 p.

Roschak, C. (2001). Vergleichende Betrachtung verschiedener Methoden zur Waldstrukturanalyse von Naturwäldern. In: Freese, J., Appelfelder, J., Roschak, C., Camphausen, A., Groth, B., Fischer, B., 2001: Mongolei – Das Khan Khentii Schutzgebiet. Reihe: Internationale und interdisziplinäre Urwaldforschung, Zentrum für Naturschutz der Univ. Göttingen, 99 p.

Freese, J., Appelfelder, J., Roschak, C., Camphausen, A., Groth, B., Fischer, B. (2001). Slowakei – Biospärenreservat Ostkarpaten, Nationalpark Poloniny. Reihe: Internationale und interdisziplinäre Urwaldforschung, Zentrum für Naturschutz der Univ. Göttingen, 88 p.

Gadow, K.v., Staupendahl, K., Roschak, C. (2000). Zur Anlage, Auswertung und Funktion von Weiserflächen, Herrn Ltd. MR Dr. H. Petri zum 80. Geburtstag, Institute for Forest Management and Yield Science, Georg-August-University, Göttingen, 10 p.

Roschak, C. (1999). Schnellwuchsuntersuchung Lensahn – Eine Untersuchung zur Bedeutung schnellwachsender Baumarten im naturnahen Waldbau, Project report for Gesellschaft zur Förderung schnellwachsender Baumarten in Norddeutschland e.V.Institut für Fortsteinrichtung und Ertragskunde der Univ. Göttingen, 38 p.

Roschak, C. (1998). Habitat-Nutzungsansprüche eines Wolfsrudels in den rumänischen Karpaten. Dipl. Arb. Univ. Göttingen, 118 p.

Promberger, C., Ionescu, O., Munteanu, I., D., Sürth, P., Petre, L., Roschak, C. (1997). Large Carnivore Project. Annual Report 1996/97, Munich Wildlife Society, Ettal, Germany. 34 p.

Promberger, C., Ionescu, O., Munteanu, I., Mertens, A., Stancu, D., Sürth, P., Petre, L., Roschak, C. (1996). Carpathian Wolf Project. Annual Report 1995/96, Munich Wildlife Society, 34p.