Office | Profile
Markus Gnuechtel and Michael Triebswetter founded GTL Gnuechtel – Triebswetter landscape architects in 1991 in Kassel, the city of the world famous nature park, the upland called Wilhelmshoehe. GTL is also active in China, where there is, starting 2005, a shared Peking office with Rainer Schmidt landscape architects. In 2007 the opening of a further office location followed in Duesseldorf.
The owners’ credo: to realise innovative designs with best possible perfection in detailed planning and project management. Participating in numerous competitions – usually announced as pan-European competitions – gives the office the opportunity to constantly break new grounds in conceptual thinking and in the final realisation and presentation of its design ideas.
Numerous awards in competitions – among them 30 mostly highest awards, e.g. the internationally highly recognised first award for Pier 40 (with TECarchitecure, Los Angeles) in Manhattan, New York, and several national and international Landscape Design Awards reflect GTL’s constant thrive for the best possible result.
When competing for the design, which is contemporary, and complies with the planning task, the basic questions at the beginning and during the design process are, however, simple: What is the spirit of the location? Were there formal and historical ideas and concepts in the past, which are related to the task? Can these historical concepts be translated into contemporary concepts of shape and material? How is the design integrated in the cultural context? The human being is in the centre of all thoughts: his longing for beauty, his love of nature as well as of art, his need for calmness as well as for hurly-burly, for certain security and excessive surprise, the way he loves to revel in memories, as well as the need for integration in the cultural context of his time.
As the task differs from project to project by nature, the replies to the basic planning tasks must turn out differently, too. Committed to the clarity of modernity and to the poetry of garden design motives and surprising design in their materials and use of details, the subsequent projects show a representative profile from the works of GTL.
Sonja Bruns
Dipl.-Ing. Landcape Architect AKHH
Corporate partner
+49 40 – 5379876 -71
| Since 2023 | Corporate Partner at GTL Landschaftsarchitektur | Triebswetter, Mauer, Bruns Partner mbB |
| Since 2022 | Member of Hamburg Chamber of Architects |
| Since 2022 | Employee at GTL |
| 2016 – 2022 | Worked at Ramboll Studio Dreiseitl, Hamburg |
| 2012 – 2016 | Worked at Gerber Architekten und Landschaftsarchitekten, Hamburg |
| 2004 – 2012 | Worked at Breimann & Bruun Landschaftsarchitekten, Hamburg |
| 1998 – 2004 | Studied Architecture at the Bauhaus University, Weimar / IUV University Venedig |
Katrin Mauer
Dipl.-Ing. Landscape Architect AKHH
Corporate partner
+49 40 – 5379876 -72
| Since 2023 | Corporate partner at GTL Landschaftsarchitektur | Triebswetter, Mauer, Bruns Partner mbB |
| Since 2022 | Employee at GTL |
| 2018 – 2022 | Worked at Breimann & Cie Landschaftsarchitektur, Hamburg |
| 2012 – 2017 | Worked at Gerber Architekten und Landschaftsarchitekten, Hamburg |
| Since 2012 | Member of Hamburg Chamber of Architects |
| 2007 – 2012 | Worked at Breimann & Bruun Landschaftsarchitekten, Hamburg |
| 2004 – 2007 | Worked at GTL in Kassel and Peking |
| 1997 – 2004 | Studied Landscape Planning at the Gesamthochschule Kassel |
Michael Triebswetter
Dipl.-Ing. Landscape Architect AKH
Corporate partner
michael.triebswetter@gtl-kassel.de
+49 561 – 78946 -38
| Since 2023 | Coroporate Partner at GTL Landschaftsarchitektur | Triebswetter, Mauer, Bruns Partner mbB |
| 2017 – 2022 | Sole proprietor of GTL | Michael Triebswetter Landschaftsarchitekt |
| 2011 – 2012 |
Visiting Professor at the University of Kassel
|
| 2008 |
Lectureship at the Technical University Munich-Weihenstephan
|
| 1994 |
Lectureship at the Gesamthochschule Kassel
|
| 1991 |
Founded his own office GTL | Gnüchtel Triebswetter Landschaftsarchitekten
|
| Until 1991 | Worked at WES & Partner, Hamburg |
| Until 1988 |
Studied Landscape Architecture at the Technical University, Munich-Weihenstephan |
Issam Abdellatif
M.A. Landscape Architecture
Project team member
Joined GTL in 2024
issam.abdellatif@gtl-hamburg.de
+49 40 – 5379876 -80
| 2011 – 2014 | Studied Landscape Architecture at Hochschule Anhalt in Bernburg |
Sadik Deniz Akman
M.Sc. Landscape Architect AKH
Project team member, Competitions, Project team leader
Joined GTL in 2015
| Since 2025 | Member of Chamber of Architects, Hesse |
| Until 2017 | Master’s degree in Urbanism and Urban Planning at Technical University of the Middle East in Ankara |
| Until 2013 | Bachelor’s degree in Landscape Architecture and Landscape Planning at Technical University of the Middle East in Ankara |
Philipp Appel
B.Sc. Landscape Architecture an Landscape Planning
Project team member
Joined GTL in 2024
+49 561 – 78946 -59
| 2018 – 2023 | Bachelor’s degree in Landscape Architecture an Landscape Planning at the University of Kassel |
Helge Baake
B.Sc. Landscape architect AKHH
Project Team Leader, Construction management
Joined GTL in 2022
+49 40 – 5379876 -74
| Since 2020 | Landscape Architect, Hamburg Chamber of Architects |
| Until 2016 | Bachelor’s degree in Landschaftscape Architecture at Technische Hochschule Ostwestfalen-Lippe in Höxter |
Jule Benedix
M.Sc. Landscape Architecture an Landscape Planning
Project team member, project leader
Joined GTL in 2015
+49 561 – 78946 -24
| Until 2018 | Studied Landscape Architecture an Landscape Planning at the University of Kassel |
Philipp-Emanuel Brandt
M.Sc. Landscape Architecture an Landscape Planning
Project leader, construction management
Joined GTL in 2016
+49 561 – 78946 -44
| Until 2016 | Studied Landscape Architecture an Landscape Planning at the University of Kassel |
Annerieke Busch
M.Eng. Landscape Architecture
Project team member
Joined GTL in 2025
annerieke.busch@gtl-hamburg.de
+49 40 – 5379876 -81
| 2022 – 2024 | Master’s degree in Landscape Architecture at Fachhochschule Erfurt |
| 2019 – 2022 | Bachelor’s degree in Landscape Architecture at Fachhochschule Erfurt |
Duy Phan Do
M.Eng. Landscape Architecture
Project team member, competitions
Joined GTL in 2018
+49 561 – 789 46 -65
| Until 2019 | Master’s degree in Landscape Architecture at University of Nürtingen-Geislingen |
| Until 2013 | Bachelor’s degree in Architecture and Planning at National University of Civil Engineering in Vietnam |
Betty Pixiang Fan
M.Eng. Art Landscape Architecture
Project team member
Joined GTL in 2009
+49 561 – 78946 -33
| Until 2008 | Master’s degree in Landscape Architecture, Anhalt University of Applied Sciences, Bernburg, Germany |
| Until 2003 | Bachelor’s degree in Landscape Architecture, Sichuan Agricultural University, Sichuan, China |
Luna Gille
B.Sc. Landscape Architecture an Landscape Planning
Project team member
Joined GTL in 2024
+49 561 – 78946 -45
| Until 2024 | Studied Landscape Architecture an Landscape Planning at the University of Kassel |
| Until 2019 | Training as a landscape gardener |
Stefanie Grebe
M.Sc. Landscape Architecture an Landscape Planning
Project team member
Joined GTL in 2025
+49 561 – 78946 -34
| 2021 – 2025 | Joined GTL as student assistent |
| 2018 – 2025 | Studied Landscape Architecture an Landscape Planning at the University of Kassel |
Sabine Gruber
B.Sc. Landscape Architecture an Landscape Planning
Acquisition, Public Relations
Joined GTL in 2020
+49 561 – 78946 -43
| Until 2016 | Bachelor’s degree in Landscape Architecture an Landscape Planning at the University of Kassel |
Yu Hao
M.Sc. Landscape Architecture an Landscape Planning
Project team member, competitions
Joined GTL in 2014
+49 561 – 78946 -49
| Until 2017 | Master’s degree in Landscape Architecture and Landscape Planning at the University of Kassel |
| Until 2010 | Bachelor’s degree in Landscape Architecture at the Beijing Forestry University in Beijing, China |
Patricia Hartung
Student, Cand. B.Sc.
Joined GTL as a student assistant in 2025
patricia.hartung@gtl-kassel.de
| Until 2026 | Study of Landscape Architecture and Landscape Planning at the University of Kassel |
Nicole Hohmann
State-accredited Business Economist
Accounting systems | Personnel management
Joined GTL in 2000
Carl Illian
Student, Cand. M.Sc.
Joined GTL as a student assistant in 2024
| Since 2021 | Study of Landscape Architecture and Landscape Planning at the University of Kassel |
Franziska Itter
Student, Cand. M.Sc.
Joined GTL as a student assistent in 2023
| Since 2020 | Study of Landscape Architecture and Landscape Planning at the University of Kassel |
Eike Janssen
Student, Cand. M.Sc.
Joined GTL as a student assistant in 2025
| Since 2025 | Master’s degree in Landscape Architecture and Landscape Planning at the University of Kassel |
| 08/24 – 02/25 | Internship at GTL in Hamburg |
| 2018 – 2023 | Bachelor’s degree in Urban Planning at the HanfenCity University of Hamburg |
Katharina Janusch
M.Sc. Landscape Architect AKH
Project team leader
Joined GTL in 2017
katharina.janusch@gtl-kassel.de
+49 561 – 78946 -39
| Until 2016 | Studied Landscape Architecture an Landscape Planning at the University of Kassel |
Stefan Kettlitz
Landscape Architect AKH bdla
Project team leader, construction management
Joined GTL in 2016
+49 561 – 78946 -21
| 2013 – 2016 | Chairperson of the Hessen Regional Association of the Federation of German Landscape Architects |
| Until 1995 | Studied Landscape Architecture an Landscape Planning at the University of Kassel |
| 1987 – 1990 | Studied for Intermediate Diploma in Landscaping at the Technical University in Munich-Weihenstephan |
| Until 1987
Until 1984 |
Work as landscape gardener in Berlin and Bern
Trained as landscape gardener in Berlin |
Juliana Klusmann
M.Sc. Landscape Architecture an Landscape Planning
Project team member, Public relations and Social Media
Joined GTL in 2025
juliana.klusmann@gtl-kassel.de
+49 561 – 78946 -55
| 2022 – 2025 | Master’s degree in Landscape Architecture and Landscape Planning at the University of Kassel |
| 2022 – 2025 | Joined GTL as Student Assistant |
| 2018 – 2022 | Bachelor’s degree in open space planning at Hochschule Osnabrück |
Stefanie Knoblich
B.Sc. Landscape Architecture an Landscape Planning
Project team member, Competition
Joined GTL in 2025
stefanie.knoblich@gtl-kassel.de
+49 40 – 5379876 -83
| 2022-2025 | Joined GTL as a Student Assistant |
| 2018-2025 | Study of Landscape Architecture and Landscape Planning at the University of Kassel |
Hannes Landau
Student, Cand. B.Sc.
Joined GTL as a student assistant in 2025
| Until 2026 | Study of Landscape Architecture and Landscape Planning at the University of Kassel |
Jingyi Li
M.A. Landscape Architecture
Project team member
Joined GTL in 2025
+49 40 – 5379876 -85
| Until 2025 | Master’s degree in Landscape Architecture at the Technical University of Munich |
| Until 2023 | Bachelor’s degree in Landscape Architecture an Landscape Planning at the Technical University of Munich |
Melanie Lips
Architect
Project leader
Joined GTL in 2012
+49 511 – 8984 -471
| Until 2003 | Studied for Diploma in Architecture at the Leibniz University Hannover |
Zhen Liu-Spieker
B.Sc. Architecture
Project team member
Joined GTL in 2025
zhen.liu-spieker@gtl-kassel.de
+49 561 – 78946 -53
| 2022 – 2025 | Project engineer at SIG Hessen Ingenieure |
| 2017 – 2021 | Working student at SMB Studio und Dümer-Haus GmbH |
| 2013 – 2022 | Bachelor’s degree in Architecture at the University of Kassel |
| 2008 – 2012 | Bachelor’s degree in Industrial Design at the Central South University in Changsha, China |
Liming Meng
M.Sc. Urban and Regional Planning
Project team member
Joined GTL in 2017
+49 561 – 78946 -58
| Until 2013 | Master’s degree in Architecture at the Brandenburg Technical University in Cottbus |
| Until 2012 | Master’s degree in Urban and Regional Planning at the Brandenburg Technical University in Cottbus |
| Until 2010 | Bachelor’s degree in Architecture at the Brandenburg Technical University in Cottbus |
| Until 2004 | Bachelor’s degree in Visual Communication at the University of Hangzhou in China |
Jannik Missing
Student, Cand. M.Sc.
Joined GTL as a student assistant in 2024
| Since 2021 | Study of Landscape Architecture and Landscape Planning, University of Kassel |
Joanna Müller
B.Sc. Landscape Architecture
Project team member
Joined GTL in 2023
+49 5271 – 6938162
| 2021 – 2023 |
Joined GTL as a Student Assistant
|
| 2018 – 2023 | Bachelor’s degree in Landscape Architecture at Technische Hochschule Ostwestfalen-Lippe in Höxter |
Sara Nejatianrad
M.Sc. Landscape Architecture
Project team member
Joined GTL in 2017
sara.nejatianrad@gtl-kassel.de
+49 561 – 78946 -48
| Until 2018 |
Master’s degree in Landscape Architecture at the Hochschule Anhalt in Bernburg
|
| Until 2011 |
Bachelor’s degree in Industrial Design at the University Mashhad in Iran
|
Frederic Omlor
M.A. Architecture
Project team member, Competition
Joined GTL in 2024
+49 681 – 9813397 -2
| Until 2024 | Studied Architecture at the Hochschule für Technik und Wirtschaft des Saarlandes |
Manuela Parra
Trainee draughtswoman
Joined GTL in 2023
Carolin Peter
M.Sc. Landscape Architecture an Landscape Planning
Competition
Joined GTL in 2025
| Until 2025 | Study of Landscape Architecture an Landscape Planning at the University of Kassel |
Philipp Schäfer
Student, Cand. M.Sc.
Joined GTL as a student assistant in 2023
philipp.schaefer@gtl-kassel.de
| Since 2020 | Study of Landscape Architecture and Landscape Planning at the University of Kassel |
Tim Schäfer
M.A. Architecture
Project team member
Joined GTL in 2025
+49 681 – 9813397 -2
| 2019 – 2022 | Masters’s degree in Architecture at the Hochschule für Technik und Wirtschaft des Saarlandes |
| 2015 – 2019 | Bachelor’s degree in Architecture at the Hochschule für Technik und Wirtschaft des Saarlandes |
Salma Sajadi
M.Sc. Sustainable Architecture and Landscape Design
Project team member
Joined GTL in 2024
+49 561 – 78946 -46
| 10/2023 – 10/2024 | Joined GTL as a Student assistant |
| 03/2023 – 09/2023 | Internship at GTL in Kassel |
| 2018 – 2019 | Metric Engineering Office in Shiraz, Iran |
| 2016 – 2017 | Avgoon architecture Office in Shiraz, Iran |
| 2010 – 2015 | Bachelor’s degree in Architecture at the Hafez University Shiraz in Iran |
Sandra Sennhenn
Dipl.-Ing. Landscape Planning
Project team leader
Joined GTL in 2010
+49 561 – 78946 -42
| Until 2010 | Studied Landscape Planning at the University of Kassel |
Tina Stamm
Dipl.-Ing. Landscape Architect AKH
Project team leader
Joined GTL in 2012
+49 561 – 78946 -40
| Until 2009 | Studied Landscape Planning at the University of Kassel |
Sibylle Triebswetter
Economist
Management
Joined GTL in 1999
sibylle.triebswetter@gtl-kassel.de
+49 561 – 78946 -10
| Until 1995 | Studied Business Management at Hochschule Osnabrück |
Pia Urban
M.Sc. Landscape Architect AKH
Project Team Leader, Construction management
Joined GTL in 2021
+49 561 – 78946 -56
| 2018 – 2021 | Joined GTL as a Student Assistant |
| Until 2021 | Studied Landscape Architecture an Landscape Planning at the University of Kassel |
Lars Weinerth
Dipl.-Ing. Landscape Architect, M.Sc. Urban Planning AKHH
Project team leader
Joined GTL in 2023
+49 40 – 5379876 -73
| Until 2009 | Master’s degree at the HafenCity University of Hamburg |
| Until 2006 | Diploma programme in Landscape Architecture at Technische Hochschule Ostwestfalen-Lippe in Höxter |
Ines Wodrich
Dipl.-Ing. Architect and Landscape Architect AKH
Project Management
Joined GTL in 2001
+49 561 – 78946 -23
| Until 2000 | Studied Architecture at the University of Kassel |
| Until 1992 | Diploma studies and engineering qualification in Building Materials and Silicate Technology at University of Freiberg |
Mingge Yu
Dipl. Designer
Project leader, Product design, Competitions
Joined GTL in 2008
+49 561 – 78946 -53
| Until 2007 | Studied Product Design at the Kunsthochschule Kassel |
| Until 2000 | Studied at the Luxun Art Academy in China |
Zhenya Yurchick
Dipl.-Ing. Landscape Architecure
Project team member
Joined GTL in 2024
zhenya.yurchick@gtl-hamburg.de
+49 40 – 5379876 -79
| Until 2011 | Studied Landscape Architecur at the Belarusian State Technological University in Minsk |
Yumeng Zhang
M.Sc. Landscape Architecture and Landscape Planning
Project team member, competitions
Joined GTL in 2016
+49 561 – 78946 -22
| Until 2017 | Master’s degree in Landscape Architecture and Landscape Planning at the University of Kassel |
| Until 2012 | Bachelor’s degree in Landscape Architecture at the Beijing Forestry University in China |
Deborah Ziehlke
Student, Cand. B.Sc.
Joined GTL as a student in 2025
| Since 2022 | Study of Landscape Architecture and Landscape Planning at the University of Kassel |
Andreas Körbs †
Landscape Architect
Project team leader, construction management
Employee at GTL from 2017 – 2024
| Until 1988 | Studied Landscaping at Hochschule Weihenstephan-Triesdorf with specialisation in space-planning |
| Until 1983 | Trained in gardening and landscaping |
I go before you into the peace of the
Lord and await you there
to eternal reunion
– St. Augustine
Obituary
Our dear colleague Andreas Körbs has left us far too soon. With his many years of experience, his professional expertise, his exceptional friendliness and his hands-on manner, he was a highly valued partner for our clients in the realisation of the most demanding construction projects. He not only supported us colleagues with advice and assistance in matters of planning and construction, he was also an attentive listener and advisor in all situations outside of work. As a fatherly mentor, he was particularly supportive of our young landscape architects. In Andreas, we are not only losing an outstanding landscape architect and a dedicated colleague, but also a friend.