About Us

Our Mission

MapleTree Veterinary Diagnostics was founded by Dr. Christopher Greenwood because of his desire to provide mobile minimally invasive diagnostic services and internal medicine consulting to improve accessibility and patient outcomes.

Our core values include excellence, responsiveness, open-mindedness, safety and empathy for veterinarians, owners and of course the animals we help. Our goal is to reduce stress and remove barriers to advanced care to improve the lives of companion animals in your community.

About Dr. Greenwood

Veterinary School: Ontario Veterinary College (Guelph, Ontario)
Internship: Veterinary Specialty Hospital of San Diego / UC-Davis Veterinary Medical Center (San Diego, California)
Residency: Ontario Veterinary College (Guelph, Ontario)

Man holding the paw of a large dog.

Dr. Greenwood completed an Internal Medicine residency at the Ontario Veterinary College. Prior to his residency, Dr. Greenwood worked in the emergency and specialty departments at the Veterinary Specialty Hospital of San Diego and UC-Davis Veterinary Medical Center, both in San Diego, California, while completing a rotating internship. After his residency, Dr.Greenwood served as a staff internist at a referral and specialty hospital in Toronto, Ontario, performing ultrasound, endoscopy, and specialty consultations as part of a compassionate referral team.

Dr. Greenwood has presented at major conferences, including the ACVIM Forum and Comparative Gastroenterology Society, and his research background includes work in hematology, gastroenterology, and bacteriology, particularly the canine fecal microbiome and fecal transplantation as a therapy for chronic gastrointestinal disease. Dr. Greenwood has lectured on Internal Medicine topics to veterinary and graduate students, clinically supervised interns and student veterinarians, instructed procedural laboratories, and led animal welfare classes. Dr. Greenwood is completing the board certification process and is currently an ACVIM Candidate. Dr. Greenwood has received several awards, including the ACVIM Clinical Excellence award. His greatest honour though remains one provided by his classmates: “Classmate who you would most want to care for your own pet".

Dr. Greenwood maintains a passion for education and believes in taking the time to answer questions and discuss every case. Knowledge is a powerful tool, and by sharing information and keeping an open mind, he hopes to empower decision-making and improve patient outcomes. Dr. Greenwood is a native of Ottawa and now lives with his wife and family in Durham. Together they live with many animals and hope to adopt as many senior homeless pets as they can manage. When Dr. Greenwood is not performing diagnostics, he can be found hiking Ontario’s trails, spending time with family, practicing languages, or at a hockey game.

About Dr. Size

Dr. Size graduated from the Ontario Veterinary College in 2016. She joined our team in 2023 after practicing in Eastern/Central Ontario. Dr. Size has worked in both regular and emergency practices and enjoys the diversity of veterinary medicine. She has always had a special interest in ultrasound. Inspired by her mentor at a young age, she also worked in Diagnostic imaging while studying at the Ontario Veterinary College. She has continued to take training courses in order to develop her skills. She is very excited to join the team and make ultrasound more accessible to the veterinary community. She shares her home with her daughter, cat Marshall and 2 rats, Lola and Millie. When Dr. Size is not taking care of her four-legged patients, she enjoys spending time with family and friends, cooking, kayaking, and travelling.

About Robyn McKnight, RVT

Robyn graduated from the Veterinary Technician program at Northern College in 2008. Originally from the Peterborough area, Robyn started out in equine practice and since graduating she has worked in small animal practice as an RVT and practice manager. With a strong interest in nutrition, behaviour and continuing her own education and learning, Robyn is also very passionate about training new technicians and team members! Robyn now calls Durham Region home with her husband and two boys, their cat Johnny and two dogs, Quinn and Libby. When not taking her boys to mountain bike events, she spends any spare time she can get with their two horses.